U.S. patent application number 13/202311 was filed with the patent office on 2012-03-01 for gold/lanthanide nanoparticle conjugates and uses thereof.
This patent application is currently assigned to COLORADO SCHOOL OF MINES. Invention is credited to Stephen G. Boyes, Misty D. Rowe.
Application Number | 20120052006 13/202311 |
Document ID | / |
Family ID | 42634197 |
Filed Date | 2012-03-01 |
United States Patent
Application |
20120052006 |
Kind Code |
A1 |
Boyes; Stephen G. ; et
al. |
March 1, 2012 |
GOLD/LANTHANIDE NANOPARTICLE CONJUGATES AND USES THEREOF
Abstract
The present disclosure is directed generally to gold/lanthanide
nanoparticle conjugates, such as gold/gadolinium nanoparticle
conjugates, nanoparticle conjugates including polymers,
nanoparticle conjugates conjugated to targeting agents and
therapeutic agents, and their use in targeting, treating, and/or
imaging disease states in a patient.
Inventors: |
Boyes; Stephen G.; (Denver,
CO) ; Rowe; Misty D.; (Golden, CO) |
Assignee: |
COLORADO SCHOOL OF MINES
Golden
CO
|
Family ID: |
42634197 |
Appl. No.: |
13/202311 |
Filed: |
February 17, 2010 |
PCT Filed: |
February 17, 2010 |
PCT NO: |
PCT/US2010/024450 |
371 Date: |
November 18, 2011 |
Related U.S. Patent Documents
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Application
Number |
Filing Date |
Patent Number |
|
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61153553 |
Feb 18, 2009 |
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Current U.S.
Class: |
424/1.29 ;
424/490; 424/78.27; 424/9.1; 424/9.32; 424/9.42; 424/9.6; 435/29;
977/810; 977/896; 977/915; 977/927; 977/928; 977/930 |
Current CPC
Class: |
A61K 9/5138 20130101;
A61K 9/5115 20130101; A61K 33/24 20130101; A61K 49/0428 20130101;
B82Y 5/00 20130101; A61K 49/0002 20130101; A61K 49/126 20130101;
A61K 49/1824 20130101; A61K 49/1878 20130101 |
Class at
Publication: |
424/1.29 ;
424/9.32; 424/9.42; 424/78.27; 435/29; 424/490; 424/9.6; 424/9.1;
977/810; 977/928; 977/930; 977/927; 977/915; 977/896 |
International
Class: |
A61K 49/00 20060101
A61K049/00; A61K 49/04 20060101 A61K049/04; A61K 31/795 20060101
A61K031/795; A61K 9/14 20060101 A61K009/14; A61K 51/12 20060101
A61K051/12; A61K 49/18 20060101 A61K049/18; C12Q 1/02 20060101
C12Q001/02 |
Claims
1. A gold/lanthanide nanoparticle comprising: a gold nanoparticle;
a lanthanide containing metal organic framework disposed on said
gold nanoparticle.
2. The nanoparticle conjugate of claim 1, wherein the lanthanide is
chosen from the group consisting of gadolinium, lanthanum, erbium,
ytterbium, neodymium, europium, terbium, cerium, thulium,
praseodymium, promethium, samarium, dysprosium, holmium, and
lutetium.
3. The nanoparticle conjugate of claim 2 wherein the lanthanide is
gadolinium.
4. A gold/lanthanide nanoparticle conjugate comprising: a gold
nanoparticle; a lanthanide containing metal organic framework
disposed on said gold nanoparticle; and a polymer, polymer
precursor, or initiator grafted onto said lanthanide containing
metal organic framework.
5. The nanoparticle conjugate according to claim 4, wherein the
polymer, polymer precursor or initiator is grafted onto the
lanthanide containing metal organic framework by a covalent bond or
non-covalent bond from a functional group selected from the group
consisting of thiolates, thioethers, thioesters, carboxylates,
amines, amides, halides, phosphonates, phosphonate esters,
phosphinates, sulphonates, sulphates, porphyrins, nitrates,
pyridine, pyridyl based compounds, nitrogen containing ligands,
oxygen containing ligands, and sulfur containing ligands.
6. The nanoparticle conjugate according to claim 5, wherein the
nanoparticle has the chemical structure of Formula (I) ##STR00017##
wherein n is an integer; and R.sub.1, R.sub.2, R.sub.3, and R.sub.4
are each independently selected from hydrogen, alkyl, substituted
alkyl, alkoxy, substituted alkoxy, acyl, substituted acyl,
acylamino, substituted acylamino, alkylamino, substituted
alkylamino, alkylsulfinyl, substituted alkylsulfinyl,
alkylsulfonyl, substituted alkylsulfonyl, alkylthio, substituted
alkylthio, alkoxycarbonyl, substituted alkoxycarbonyl, aryl,
substituted aryl, arylalkyl, substituted arylalkyl, aryloxy,
substituted aryloxy, aryloxycarbonyl, substituted aryloxycarbonyl,
carbamoyl, substituted carbamoyl, cycloalkyl, substituted
cycloalkyl, cycloheteroalkyl, substituted cycloheteroalkyl,
dialkylamino, substituted dialkylamino, halo, heteroalkyl,
substituted heteroalkyl, heteroaryl, substituted heteroaryl,
heteroarylalkyl, substituted heteroarylalkyl, heteroalkyloxy,
substituted heteroalkyloxy, heteroaryloxy and substituted
heteroaryloxy.
7. The nanoparticle conjugate according to claim 6, further
comprising one or more additional functional groups.
8. The nanoparticle conjugate according to claim 7, wherein the one
or more additional functional groups are selected from the group
consisting of carboxylic acids and carboxylic acid salt
derivatives, acid halides, sulfonic acids and sulfonic acid salts,
anhydride derivatives, hydroxyl derivatives, amine and amide
derivatives, silane derivations, phosphate derivatives, nitro
derivatives, succinimide and sulfo-containing succinimide
derivatives, halide derivatives, alkene derivatives, morpholine
derivatives, cyano derivatives, epoxide derivatives, ester
derivatives, carbazole derivatives, azide derivatives, alkyne
derivatives, acid containing sugar derivatives, glycerol analogue
derivatives, maleimide derivatives, protected acids and alcohols,
and acid halide derivatives.
9. The nanoparticle conjugate of claim 7, further comprising an
imaging agent covalently bonded to said polymer.
10. The nanoparticle conjugate of claim 9, wherein the imaging
agent is a fluorescent monomer.
11. The nanoparticle conjugate of claim 10, wherein the fluorescent
monomer is poly(fluorescein-O-methacrylate)(PFMA).
12. The nanoparticle conjugate of claim 7 further comprising a
therapeutic agent covalently bonded to said polymer.
13. The nanoparticle conjugate of claim 7 further comprising a
targeting agent covalently bonded to said polymer.
14. A pharmaceutical composition comprising: a nanoparticle
conjugate of claim 1, and; a pharmaceutically acceptable
carrier.
15. A method of diagnosing a disease or disorder comprising:
administering an effective amount of the nanoparticle conjugate of
claim 1 to a patient in need of a diagnosis of said disease or
disorder.
16. A method of treating a disease or disorder comprising:
administering an effective amount of the nanoparticle conjugate of
claim 1 to a patient in need of treatment of said disease or
disorder.
17. A method of imaging tissue comprising: administering an
effective amount of the nanoparticle conjugate of claim 1 to a
patient; and exposing said patient to Nuclear Magnetic Resonance or
Computed X-ray Tomography, or exposing samples of the patient's
tissue to optical imaging.
18. A pharmaceutical composition comprising: a nanoparticle
conjugate of claim 14, and a pharmaceutically acceptable
carrier.
19. A method of diagnosing a disease or disorder comprising:
administering an effective amount of the nanoparticle conjugate of
claim 4 to a patient in need of a diagnosis of said disease or
disorder.
20. A method of treating a disease or disorder comprising:
administering an effective amount of the nanoparticle conjugate of
claim 4 to a patient in need of treatment of said disease or
disorder.
21. A method of imaging tissue comprising: administering an
effective amount of the nanoparticle conjugate of claim 4 to a
patient in need of imaging; and obtaining an image of the patient
or of a portion of said patient.
22. A method of imaging tissue of claim 21 wherein the imaging
technique is chosen from one or more of the group consisting of;
nuclear magnetic imaging, positron emission tomography, computed
x-ray tomography, dark field confocal microscopy, light field
confocal microscopy, optical imaging.
23. A method of making a nanoparticle conjugate comprising:
contacting a compound of Formula (I) or Formula (II) or salt
thereof with a compound of Formula (V) or a salt thereof to form
the compound of Formula (VI): ##STR00018## contacting the compound
of Formula (VI) with a gold nanoparticle disposed to a gadolinium
containing metal organic framework to form a gold/gadolinium
nanoparticle conjugate; wherein n is an integer, and R.sub.2,
R.sub.3, R.sub.4, R.sub.7, and R.sub.8 are each independently
selected from hydrogen, alkyl, substituted alkyl, alkoxy,
substituted alkoxy, acyl, substituted acyl, acylamino, substituted
acylamino, alkylamino, substituted alkylamino, alkylsulfinyl,
substituted alkylsulfinyl, alkylsulfonyl, substituted
alkylsulfonyl, alkylthio, substituted alkylthio, alkoxycarbonyl,
substituted alkoxycarbonyl, aryl, substituted aryl, arylalkyl,
substituted arylalkyl, aryloxy, substituted aryloxy,
aryloxycarbonyl, substituted aryloxycarbonyl, carbamoyl,
substituted carbamoyl, cycloalkyl, substituted cycloalkyl,
cycloheteroalkyl, substituted cycloheteroalkyl, dialkylamino,
substituted dialkylamino, halo, heteroalkyl, substituted
heteroalkyl, heteroaryl, substituted heteroaryl, heteroarylalkyl,
substituted heteroarylalkyl, heteroalkyloxy, substituted
heteroalkyloxy, heteroaryloxy and substituted heteroaryloxy, to
form a gadolinium nanoparticle conjugate with the compounds of
formula (I).
24. A method of making a nanoparticle conjugate comprising:
contacting a compound of Formula (I) or Formula (II) or salt
thereof with a compound of Formula (V) or a salt thereof to form
the compound of Formula (VI): ##STR00019## contacting the compound
of Formula (VI) with a gold nanoparticle disposed to a gadolinium
containing metal organic framework to form a gold/gadolinium
nanoparticle conjugate; wherein n is an integer, and R.sub.2,
R.sub.3, R.sub.4, R.sub.5, and R.sub.5 are each independently
selected from hydrogen, alkyl, substituted alkyl, alkoxy,
substituted alkoxy, acyl, substituted acyl, acylamino, substituted
acylamino, alkylamino, substituted alkylamino, alkylsulfinyl,
substituted alkylsulfinyl, alkylsulfonyl, substituted
alkylsulfonyl, alkylthio, substituted alkylthio, alkoxycarbonyl,
substituted alkoxycarbonyl, aryl, substituted aryl, arylalkyl,
substituted arylalkyl, aryloxy, substituted aryloxy,
aryloxycarbonyl, substituted aryloxycarbonyl, carbamoyl,
substituted carbamoyl, cycloalkyl, substituted cycloalkyl,
cycloheteroalkyl, substituted cycloheteroalkyl, dialkylamino,
substituted dialkylamino, halo, heteroalkyl, substituted
heteroalkyl, heteroaryl, substituted heteroaryl, heteroarylalkyl,
substituted heteroarylalkyl, heteroalkyloxy, substituted
heteroalkyloxy, heteroaryloxy and substituted heteroaryloxy, to
form a gadolinium nanoparticle conjugate with the compounds of
formula (I).
25. The method of claim 19, further comprising a step of contacting
a reducing agent to the compound of Formula (I) before contacting
said nanoparticle with said compound of Formula (I).
Description
CROSS REFERENCE TO RELATED APPLICATIONS
[0001] This application claims priority to U.S. Patent Application
No. 61/153,553 filed Feb. 18, 2009, and entitled "Gold/Lanthanide
Nanoparticle Conjugates and Uses Thereof", which is hereby
incorporated by reference in its entirety.
[0002] This application is related to U.S. patent application Ser.
No. 12/197,044 filed Aug. 22, 2008, and entitled "Gold Nanoparticle
Conjugates and Uses Thereof," and U.S. patent application Ser. No.
12/197,061 filed Aug. 22, 2008, entitled "Lanthanide Nanoparticle
Conjugates and Uses Thereof", each of which is hereby incorporated
by reference in its entirety.
FIELD
[0003] The disclosure generally relates to multimodal imaging
agents. Specifically, this disclosure relates to gold/lanthanide
nanoparticles with and without polymers grafted to, or polymerized
from, the surface of lanthanide, e.g. gadolinium, nanoparticles.
The polymers have functional groups that may be derivativized to
include imaging agents, therapeutic agents, and targeting agents at
their surface. Use of these multimodal nanoparticles will allow
targeted delivery of imaging agents, and therapeutic compounds to
specific cells, tissues, and organs.
BACKGROUND
[0004] Nanomedicine, according to the National Institutes of
Health, refers to highly specific medical intervention at the
molecular scale for diagnosis, prevention, and treatment of
diseases. [Park, K. J. Controlled Release 2007, 120, 1-3]. One
example nanomedicine is the use of nanodevices designed to image,
target, and treat cancer.
[0005] Nanodevices could accomplish these disparate tasks through
the use of agents or moieties associated with nanoparticles. The
nanoparticles themselves may possess inherent capabilities (such as
gadolinium nanoparticles used in to enhance magnetic resonance
imaging or goldnanoparticles used to concentrate the energy of
infrared lasers fo the thermoablation of cancer cells).
Alternatively agents may be attached to the nanoparticle to provide
specific capabilities such as antibodies directed against a
specific tumor marker, or a chemotherapeutic compound attached to
the nanoparticle.
[0006] Intravascularly injectable nanodevices (referred to as
"theragnostic devices") are being developed for the treatment of
cancer. However, there are problems with present manufacturing
techniques for theragnostic devices. These manufacturing problems
lead to poor loading efficiencies, low loading capacity, and the
inability to control nanodevice production parameters such as size
distribution, surface interactions, and in vivo performance. [Park,
K. J. Controlled Release 2007, 120, 1-3]. Current design
limitations also impact flexibility in choosing the type and
quantity of incorporated moiety (drug and/or targeting agent).
Another problem with the development of nanodevices is the lack of
control over spatial orientation and architecture of the
nanoparticle. Finally, nanodevices suffer from instability of the
drug and/or targeting agent associated with the nanoparticle.
[0007] Multimodal imaging agents have the potential to overcome
many of the limitations of current clinical imaging agents by
providing a route to achieve diagnostic imaging, targetting, and
therapy with administration of a single nanodevice. Combining these
different capablities will reduce patient anxiety and
discomfort.
[0008] Against this backdrop, the present disclosure has been
developed
SUMMARY
[0009] The present disclosure is directed generally to
gold/lanthanide nanoparticle conjugates, such as gold/gadolinium
nanoparticle conjugates, nanoparticle conjugates including
polymers, conjugation to targeting agents and therapeutic agents,
and their use in targeting, treating, and/or imaging disease states
in a patient. In certain embodiments, the gold/gadolinium
nanoparticle conjugates are multifunctional polymeric systems.
Biocompatible polymer backbones that can be conjugated to imaging
agents, targeting agents, and therapeutic agents are produced.
Post-polymerization modification of the polymer backbone allows
attachment of targeting agents or therapeutic agents to a
functional group. The resulting gadolinium nanoparticle conjugates
provide the ability to target, treat, and image diseased cells.
[0010] In one aspect, gold/gadolinium nanoparticle conjugates are
provided. The conjugate includes a gold nanoparticle coated with a
gadolinium metal organic framework and a polymer or polymer
precursor containing a functional group grafted to the
nanoparticle. As used herein, polymer precursors include components
of polymers, such as monomers, dimers, etc., or initiators bonded
to the nanoparticle prior to polymerization. In various aspects,
the functional group is selected from the group consisting of
thiolates, thioethers, thioesters, carboxylates, amines, amides,
halides, phosphonates, phosphonate esters, phosphinates,
sulphonates, sulphates, porphyrins, nitrates, pyridine, pyridyl
based compounds, nitrogen containing ligands, oxygen containing
ligands, and sulfur containing ligands. In certain embodiments, the
polymer, polymer precursor or initiator can be grafted onto the
nanoparticle by a covalent or non-covalent bond between a
functional group and nanoparticle. In certain embodiments, the
functional group is a single thiol group and vacant orbital present
on the gadolinium (III) cation. In further aspects, the
gold/gadolinium nanoparticle conjugate can have the chemical
structure according to Formula (I):
##STR00001##
[0011] wherein n is an integer;
[0012] R.sub.1, R.sub.2, R.sub.3, and R.sub.4 are each
independently selected from hydrogen, alkyl, substituted alkyl,
alkoxy, substituted alkoxy, acyl, substituted acyl, acylamino,
substituted acylamino, alkylamino, substituted alkylamino,
alkylsulfinyl, substituted alkylsulfinyl, alkylsulfonyl,
substituted alkylsulfonyl, alkylthio, substituted alkylthio,
alkoxycarbonyl, substituted alkoxycarbonyl, aryl, substituted aryl,
arylalkyl, substituted arylalkyl, aryloxy, substituted aryloxy,
aryloxycarbonyl, substituted aryloxycarbonyl, carbamoyl,
substituted carbamoyl, cycloalkyl, substituted cycloalkyl,
cycloheteroalkyl, substituted cycloheteroalkyl, dialkylamino,
substituted dialkylamino, halo, heteroalkyl, substituted
heteroalkyl, heteroaryl, substituted heteroaryl, heteroarylalkyl,
substituted heteroarylalkyl, heteroalkyloxy, substituted
heteroalkyloxy, heteroaryloxy and substituted heteroaryloxy.
[0013] In other embodiments, R.sub.2 includes a functional group
selected from thiolates, thioethers, thioesters, carboxylates,
amines, amides, halides, phosphonates, phosphonate esters,
phosphinates, sulphonates, sulphates, porphyrins, nitrates,
pyridine, pyridyl based compounds, nitrogen containing ligands,
oxygen containing ligands, and sulfur containing ligands.
[0014] The nanoparticle conjugate can further include a functional
group. In certain variations, the functional group can be selected
from carboxylic acids and carboxylic acid salt derivatives, acid
halides, sulfonic acids and sulfonic acid salts, anhydride
derivatives, hydroxyl derivatives, amine and amide derivatives,
silane derivations, phosphate derivatives, nitro derivatives,
succinimide and sulfo-containing succinimide derivatives, halide
derivatives, alkene derivatives, morpholine derivatives, cyano
derivatives, epoxide derivatives, ester derivatives, carbazole
derivatives, azide derivatives, alkyne derivatives, acid containing
sugar derivatives, glycerol analogue derivatives, maleimide
derivatives, protected acids and alcohols, and acid halide
derivatives.
[0015] In other variations, the nanoparticle conjugate includes a
therapeutic agent. In further variations, the nanoparticle further
includes a targeting agent. Both the therapeutic agent and
targeting agent are bonded to the polymer, optionally they are
bonded to the polymer via a covalent linker or functional
group.
[0016] In another aspect, the disclosure is directed to a
pharmaceutical composition comprising the gold/gadolinium
nanoparticle conjugate as described herein, and a pharmaceutically
acceptable carrier.
[0017] In a further aspect, the disclosure is directed to methods
of making nanoparticle conjugates. A nanoparticle having a suitable
initiator is contacted with a dithioester, xanthate, or
dithiocarbamate of Formula (II) or a trithiocarbonate of Formula
(III):
##STR00002##
[0018] wherein
[0019] R.sub.5, R.sub.6, R.sub.7, and R.sub.8 are each
independently selected from hydrogen, alkyl, substituted alkyl,
alkoxy, substituted alkoxy, acyl, substituted acyl, acylamino,
substituted acylamino, alkylamino, substituted alkylamino,
alkylsulfinyl, substituted alkylsulfinyl, alkylsulfonyl,
substituted alkylsulfonyl, alkylthio, substituted alkylthio,
alkoxycarbonyl, substituted alkoxycarbonyl, aryl, substituted aryl,
arylalkyl, substituted arylalkyl, aryloxy, substituted aryloxy,
aryloxycarbonyl, substituted aryloxycarbonyl, carbamoyl,
substituted carbamoyl, cycloalkyl, substituted cycloalkyl,
cycloheteroalkyl, substituted cycloheteroalkyl, dialkylamino,
substituted dialkylamino, halo, heteroalkyl, substituted
heteroalkyl, heteroaryl, substituted heteroaryl, heteroarylalkyl,
substituted heteroarylalkyl, heteroalkyloxy, substituted
heteroalkyloxy, heteroaryloxy and substituted heteroaryloxy.
[0020] In other embodiments, R.sub.6 and R.sub.8 are each
independently selected from a dithioester, xanthate,
dithiocarbamate and trithiocarbonate to form a nanoparticle
conjugate with the compounds of Formulae (II) or (III).
Alternatively, the polymer or polymer precursor can be treated with
a reducing agent to the compound of Formulae (II) or (III) before
contacting said gold/gadolinium nanoparticle with said compound of
formula (II) or (III).
[0021] In further aspects, the disclosure is directed to a method
of treating a disease or disorder by administering a
gold/gadolinium nanoparticle conjugate to a patient in need of
treatment of said disease or disorder. In various embodiments, the
targeting agent localizes the nanoparticle conjugate to the site of
the disease or disorder. The therapeutic agent treats said disease
or disorder. The method can be further combined with imaging the
nanoparticle conjugate at the disease location.
BRIEF DESCRIPTION OF THE DRAWINGS
[0022] The disclosed Figures are exemplary, and are not intended to
be limiting of the claims.
[0023] FIG. 1 depicts preparation of polymer modified surfaces by
the (a) physisorption, (b) `grafting to`, and (c) `grafting from`
methods, (d) depicts a proposed coordination mechanism attachment
of thiolate polymer chain ends to MOFs of Gd nanoparticles (NPs)
synthesized by a reverse microemulsion system employing the 1,4-BDC
ligand.
[0024] FIG. 2 depicts the mushroom to brush spatial transition of
polymers at a surface.
[0025] FIG. 3 depicts exemplary targeting molecules (folic acid or
an RGD sequence) and exemplary therapeutic agents (the cancer
therapeutics paclitaxel or methotrexate) binding to a
functionalized polymer grafted to a nanoparticle.
[0026] FIG. 4 depicts .sup.1H NMR spectrum analysis of copolymer
binding. (a) depicts a .sup.1H NMR spectrum of
PNIPAM-co-PNAOS-co-PFMA copolymer, (b) depicts a .sup.1H NMR
spectrum of folic acid, (c) depicts a .sup.1H NMR spectrum of
PNIPAM-co-PNAOS-co-PFMA copolymer reacted with folic acid.
[0027] FIG. 5 depicts fluorescence images of
PNIPAM-co-PNAOS-co-PFMA modified gold/Gd nanoparticles.
[0028] FIG. 6 depicts transmission electron microscopy (TEM) images
of (a) unmodified gold nanoparticles (Au NPs), (b) gold/gadolinium
(Au/Gd) nanoparticles, and (c) PNIPAM homopolymer modified gold/Gd
nanoparticles
[0029] FIG. 7 depicts UV-Vis spectra of virgin gold nanoparticles,
gold-gadolinium (Au--Gd) hybrid nanoparticles, and
poly(N-isopropylacrylamide) modified Au--Gd hybrid
nanoparticles
[0030] FIG. 8 depicts ATR-FTIR (attenuated total reflection-fourier
transform infrared) spectra of gold-gadolinium (Au/Gd)
nanoparticles, poly(N-isopropylacrylamide) (PNIPAM) homopolymer
synthesized via RAFT polymerization, and PNIPAM modified Au--Gd
hybrid nanoparticles.
[0031] FIG. 9 depicts cell inhibition studies for unmodified gold
nanoparticles and Au--Gd hybrid nanoparticles, homopolymer modified
gold/Gd nanoparticles, and the reversible addition-fragmentation
chain transfer (RAFT) copolymer, PNIPAM-co-PNAOS-co-PFMA.
DETAILED DESCRIPTION
[0032] There has been an increasing focus on the development of
multifunctional nanomedicines for improvement in the remedial
results of drug treatment for cancer patients. See, e.g.,
Kukowska-Latallo, et al., Cancer Res. 2005, 65, 5317-5324. Sau, T.
K. et al., Langmuir 2004, 20, 6414-6420; and Niidome, T. et al.,
Journal of Controlled Release 2006, 114, 343-347. Multifunctional
nanomedicines incorporate diagnostic imaging capabilities,
targeting through biomolecular recognition, and a therapeutic agent
for treatment of a specific disease, providing a "one dose"
approach of overcoming downfalls of conventional treatment and
imaging techniques.
[0033] The disclosure relates to nanoparticles having both gold and
gadolinium. In various aspects, the nanoparticles have application
as multimodal, targeting, imaging, and/or therapeutic agents for
the diagnosis and treatment of specific diseases. The gadolinium
can act as a positive contrast agent for magnetic resonance imaging
(MRI), and the gold nanoparticle can be used, for example, in
computed X-Ray tomography (CT) as well as optical and dark field
confocal microscopy. The gold nanoparticle may also be used to
thermally ablate tumor cells with infrared, near-infrared light, or
other wavelength energy. Furthermore, these nanoparticles have been
surface modified with polymers prepared by reversible
addition-fragmentation chain transfer (RAFT) polymerization that
contain fluorescent monomers to enable fluorescence imaging of the
modified particles. Using the previously disclosed procedure for
modifying gadolinium nanoparticles with RAFT polymers, cancer
targeting ligands, such as folic acid and G-RGD sequences, and
cancer therapeutics, such as methotrexate, doxorubicin, and
paclitaxel, can be added to the surface of the nanoparticles to
enable the targeted imaging and treatment of various cancers.
[0034] The gold nanoparticle is coated with a gadolinium metal
organic framework by disposing the gadolinium metal organic
framework on or onto the gold nanoparticle. The interaction between
the gold nanoparticle and the metal organic framework may include
covalent as well as noncovalent interations. Without being limited
by examples the interactions between the nanoparticle and metal
organic framework may be ionic, hydrogen bonding, dipole-dipole,
and Van der Waals forces.
DEFINITIONS
[0035] A dash ("-") that is not between two letters or symbols is
used to indicate a point of attachment for a moiety or substituent.
For example, --CONH.sub.2 is attached through the carbon atom.
[0036] "Acyl" by itself or as part of another substituent refers to
a radical --C(O)R.sub.30, where R.sub.30 is hydrogen, alkyl,
cycloalkyl, cycloheteroalkyl, aryl, arylalkyl, heteroalkyl,
heteroaryl or heteroarylalkyl as defined herein. Representative
examples include, but are not limited to formyl, acetyl,
cyclohexylcarbonyl, cyclohexylmethylcarbonyl, benzoyl,
benzylcarbonyl and the like.
[0037] "Acylamino" by itself or as part of another substituent
refers to a radical --NR.sup.31C(O)R.sup.32, where R.sup.31 and
R.sup.32 are independently hydrogen, alkyl, cycloalkyl,
cycloheteroalkyl, aryl, arylalkyl, heteroalkyl, heteroaryl or
heteroarylalkyl as defined herein. Representative examples include,
but are not limited to formamido, acetamido and benzamido.
[0038] "Acyloxy" by itself or as part of another substituent refers
to a radical --OC(O)R.sup.33, where R.sup.33 is alkyl, cycloalkyl,
cycloheteroalkyl, aryl, arylalkyl, heteroalkyl, heteroaryl or
heteroarylalkyl as defined herein. Representative examples include,
but are not limited to acetoxy, isobutyroyloxy, benzoyloxy,
phenylacetoxy and the like
[0039] "Alkanyl" by itself or as part of another substituent refers
to a saturated branched, straight-chain or cyclic alkyl radical
derived by the removal of one hydrogen atom from a single carbon
atom of a parent alkane. In some embodiments, an alkanyl group
comprises from 1 to 20 carbon atoms. In other embodiments, an
alkanyl group comprises from 1 to 10 carbon atoms. In still other
embodiments, an alkanyl group comprises from 1 to 6 carbon atoms.
Typical alkanyl groups include, but are not limited to, methanyl;
ethanyl; propanyls such as propan-1-yl, propan-2-yl (isopropyl),
cyclopropan-1-yl, etc.; butanyls such as butan-1-yl, butan-2-yl
(sec-butyl), 2-methyl-propan-1-yl (isobutyl), 2-methyl-propan-2-yl
(t-butyl), cyclobutan-1-yl, etc.; and the like.
[0040] "Alkenyl" by itself or as part of another substituent refers
to an unsaturated branched, straight-chain or cyclic alkyl radical
having at least one carbon-carbon double bond derived by the
removal of one hydrogen atom from a single carbon atom of a parent
alkene. The group may be in either the cis or trans conformation
about the double bond(s). In some embodiments, an alkenyl group
comprises from 1 to 20 carbon atoms. In other embodiments, an
alkenyl group comprises from 1 to 10 carbon atoms. In still other
embodiments, an alkenyl group comprises from 1 to 6 carbon atoms.
Typical alkenyl groups include, but are not limited to, ethenyl;
propenyls such as prop-1-en-1-yl, prop-1-en-2-yl, prop-2-en-1-yl
(allyl), prop-2-en-2-yl, cycloprop-1-en-1-yl; cycloprop-2-en-1-yl;
butenyls such as but-1-en-1-yl, but-1-en-2-yl,
2-methyl-prop-1-en-1-yl, but-2-en-1-yl, but-2-en-1-yl,
but-2-en-2-yl, buta-1,3-dien-1-yl, buta-1,3-dien-2-yl,
cyclobut-1-en-1-yl, cyclobut-1-en-3-yl, cyclobuta-1,3-dien-1-yl,
etc.; and the like.
[0041] "Alkoxy" by itself or as part of another substituent refers
to a radical --OR.sup.34 where R.sup.34 represents an alkyl or
cycloalkyl group as defined herein. Representative examples
include, but are not limited to, methoxy, ethoxy, propoxy, butoxy,
cyclohexyloxy and the like.
[0042] "Alkoxycarbonyl" by itself or as part of another substituent
refers to a radical --C(O)--OR.sup.35 where R.sup.35 represents an
alkyl or cycloalkyl group as defined herein. Representative
examples include, but are not limited to, methoxycarbonyl,
ethoxycarbonyl, propoxycarbonyl, butoxycarbonyl,
cyclohexyloxycarbonyl and the like.
[0043] "Alkoxycarbonylamino" by itself or as part of another
substituent refers to a radical --NR.sup.36C(O)--OR.sup.37 where
R.sup.36 represents an alkyl or cycloalkyl group and R.sup.37 is
alkyl, cycloalkyl, cycloheteroalkyl, aryl, arylalkyl, heteroalkyl,
heteroaryl, heteroarylalkyl as defined herein. Representative
examples include, but are not limited to, methoxycarbonylamino,
tert-butoxycarbonylamino and benzyloxycarbonylamino.
[0044] "Alkoxycarbonyloxy" by itself or as part of another
substituent refers to a radical --OC(O)--OR.sup.38 where R.sup.38
represents an alkyl or cycloalkyl group as defined herein.
Representative examples include, but are not limited to,
methoxycarbonyloxy, ethoxycarbonyloxy and
cyclohexyloxycarbonyloxy.
[0045] "Alkyl" by itself or as part of another substituent refers
to a saturated or unsaturated, branched, straight-chain or cyclic
monovalent hydrocarbon radical derived by the removal of one
hydrogen atom from a single carbon atom of a parent alkane, alkene
or alkyne. Typical alkyl groups include, but are not limited to,
methyl; ethyls such as ethanyl, ethenyl, ethynyl; propyls such as
propan-1-yl, propan-2-yl, cyclopropan-1-yl, prop-1-en-1-yl,
prop-1-en-2-yl, prop-2-en-1-yl (allyl), cycloprop-1-en-1-yl;
cycloprop-2-en-1-yl, prop-1-yn-1-yl, prop-2-yn-1-yl, etc.; butyls
such as butan-1-yl, butan-2-yl, 2-methyl-propan-1-yl,
2-methyl-propan-2-yl, cyclobutan-1-yl, but-1-en-1-yl,
but-1-en-2-yl, 2-methyl-prop-1-en-1-yl, but-2-en-1-yl,
but-2-en-2-yl, buta-1,3-dien-1-yl, buta-1,3-dien-2-yl,
cyclobut-1-en-1-yl, cyclobut-1-en-3-yl, cyclobuta-1,3-dien-1-yl,
but-1-yn-1-yl, but-1-yn-3-yl, but-3-yn-1-yl, etc.; and the
like.
[0046] "Alkyl" is specifically intended to include groups having
any degree or level of saturation, i.e., groups having exclusively
single carbon-carbon bonds, groups having one or more double
carbon-carbon bonds, groups having one or more triple carbon-carbon
bonds and groups having mixtures of single, double and triple
carbon-carbon bonds. Where a specific level of saturation is
intended, the expressions "alkanyl," "alkenyl," and "alkynyl" are
used. In some embodiments, an alkyl group comprises from 1 to 20
carbon atoms. In other embodiments, an alkyl group comprises from 1
to 10 carbon atoms. In still other embodiments, an alkyl group
comprises from 1 to 6 carbon atoms.
[0047] "Alkylamino" means a radical --NHR where R represents an
alkyl or cycloalkyl group as defined herein. In certain
embodiments, an alkoxy group is C.sub.1-18 alkoxy, in certain
embodiments, C.sub.1-12 alkoxy, in certain embodiments, C.sub.1-8
alkoxy, in certain embodiments, C.sub.1-6 alkoxy, in certain
embodiments, C.sub.1-4 alkoxy, and in certain embodiments,
C.sub.1-3 alkoxy. Representative examples include, but are not
limited to, methylamino, ethylamino, 1-methylethylamino, cyclohexyl
amino and the like.
[0048] "Alkylsulfinyl" refers to a radical --S(O)R where R is an
alkyl or cycloalkyl group as defined herein. Representative
examples include, but are not limited to, methylsulfinyl,
ethylsulfinyl, propylsulfinyl, butylsulfinyl and the like.
[0049] "Alkylsulfonyl" refers to a radical --S(O).sub.2R where R is
an alkyl or cycloalkyl group as defined herein. Representative
examples include, but are not limited to, methylsulfonyl,
ethylsulfonyl, propylsulfonyl, butylsulfonyl and the like.
[0050] "Alkylthio" refers to a radical --SR where R is an alkyl or
cycloalkyl group as defined herein that may be optionally
substituted as defined herein. Representative examples include, but
are not limited to methylthio, ethylthio, propylthio, butylthio and
the like.
[0051] "Alkynyl" by itself or as part of another substituent refers
to an unsaturated branched, straight-chain or cyclic alkyl radical
having at least one carbon-carbon triple bond derived by the
removal of one hydrogen atom from a single carbon atom of a parent
alkyne. In some embodiments, an alkynyl group comprises from 1 to
20 carbon atoms. In other embodiments, an alkynyl group comprises
from 1 to 10 carbon atoms. In still other embodiments, an alkynyl
group comprises from 1 to 6 carbon atoms. Typical alkynyl groups
include, but are not limited to, ethynyl; propynyls such as
prop-1-yn-1-yl, prop-2-yn-1-yl, etc.; butynyls such as
but-1-yn-1-yl, but-1-yn-3-yl, but-3-yn-1-yl, etc.; and the
like.
[0052] "Amide derivatives" as used herein refer to compounds having
the structure RC(O)NR'R''. The R, R' and R'' in amide derivatives
can each independently be any desired substituent, including but
not limited to hydrogen, halides, and substituted or unsubstituted
alkyl, alkoxy, aryl or acyl groups. The amine or amide group can be
used as the point of attachment to a therapeutic or targeting
group, optionally via a linker. Examples of amines and amides
include, but are not limited to, 2-(N,N-diethylamino)ethyl
methacrylate, 2-(N,N-diethylamino)ethyl acrylate,
N[2-(N,N-dimethylamino)ethyl]methacrylamide,
N-[3-(N,N-dimethylamino)propyl]acrylamide, diallylamine,
methacryloyl-L-lysine, 2-(tert-butylamino)ethyl methacrylate,
N-(3-aminopropyl)methacrylamide hydrochloride,
3-dimethylaminoneopentyl acrylate,
N-(2-hydroxypropyl)methacrylamide, N-methacryloyl tyrosine amide,
2-diisopropylaminoethyl methacrylate, 3-dimethylaminoneopentyl
acrylate, 2-aminoethyl methacrylate hydrochloride,
hydroxymethyldiacetoneacrylamide,
N-(iso-butoxymethyl)methacrylamide and N-methylolacrylamide.
[0053] "Amine derivatives" are compound or radicals thereof having
a functional group containing at least one nitrogen, and having the
structure RNR'R''. R, R' and R'' in amine derivatives can each
independently be any desired substituent, including but not limited
to hydrogen, halides, and substituted or unsubstituted alkyl,
alkoxy, aryl or acyl groups.
[0054] "Anhydride derivatives" as used herein refer to a compound
or radical having the chemical structure R1C(O)OC(O)R2. The
carboxyl groups, optionally after removal of R.sup.1 or R.sup.2
groups, can be used as the point of attachment to a therapeutic or
targeting group, optionally via a linker. Examples of anhydride
derivatives include, but are not limited to, acrylic anhydride,
methacrylic anhydride, maleic anhydride, and 4-methacryloxyethyl
trimellitic anhydride
[0055] "Antibody" refers to a monomeric or multimeric protein
comprising one or more polypeptide chains that binds specifically
to an antigen. An antibody can be a full length antibody or an
antibody fragment.
[0056] "Antibody, full length antibody," herein is meant the
structure that constitutes the natural biological form of an
antibody, including variable and constant regions. For example, in
most mammals, including humans and mice, the full length antibody
of the IgG class is a tetramer and consists of two identical pairs
of two immunoglobulin chains, each pair having one light and one
heavy chain, each light chain comprising immunoglobulin domains
V.sub.L and C.sub.L, and each heavy chain comprising immunoglobulin
domains V.sub.H, C.sub.H1, (C.gamma.1), C.sub.H2 (C.gamma.2), and
C.sub.H3 (C.gamma.3). In some mammals, for example in camels and
llamas, IgG antibodies may consist of only two heavy chains, each
heavy chain comprising a variable domain attached to the Fc
region.
[0057] "Antibody fragments" are portions of full length antibodies
that bind antigens. Specific antibody fragments include, but are
not limited to, (i) the Fab fragment consisting of V.sub.L,
V.sub.H, C.sub.L and C.sub.H1 domains, (ii) the Fd fragment
consisting of the V.sub.H and C.sub.H1 domains, (iii) the Fv
fragment consisting of the V.sub.L and V.sub.H domains of a single
antibody; (iv) the dAb fragment (Ward et al., 1989, Nature
341:544-546) which consists of a single variable, (v) isolated CDR
regions, (vi) F(ab')2 fragments, a bivalent fragment comprising two
linked Fab fragments (vii) single chain Fv molecules (scFv),
wherein a V.sub.H domain and a V.sub.L domain are linked by a
peptide linker which allows the two domains to associate to form an
antigen binding site (Bird et al., 1988, Science 242:423-426,
Huston et al., 1988, Proc. Natl. Acad. Sci. U.S.A. 85:5879-5883),
(viii) bispecific single chain Fv dimers (PCT/US92/09965) and (ix)
"diabodies" or "triabodies", multivalent or multispecific fragments
constructed by gene fusion (Tomlinson et. al., 2000, Methods
Enzymol. 326:461-479; WO94/13804; Holliger et al., 1993, Proc.
Natl. Acad. Sci. U.S.A. 90:6444-6448). In certain embodiments,
antibodies are produced by recombinant DNA techniques. Other
examples of antibody formats and architectures are described in
Holliger & Hudson, 2006, Nature Biotechnology 23(9):1126-1136,
and Carter 2006, Nature Reviews Immunology 6:343-357 and references
cited therein, all expressly incorporated by reference. In
additional embodiments, antibodies are produced by enzymatic or
chemical cleavage of naturally occurring antibodies.
[0058] "Aromatic Ring System" by itself or as part of another
substituent refers to an unsaturated cyclic or polycyclic ring
system radical having a conjugated it electron system. Specifically
included within the definition of "aromatic ring system" are fused
ring systems in which one or more of the rings are aromatic and one
or more of the rings are saturated or unsaturated, such as, for
example, fluorene, indane, indene, phenalene, etc. Typical aromatic
ring systems include, but are not limited to, aceanthrylene,
acenaphthylene, acephenanthrylene, anthracene, azulene, benzene,
chrysene, coronene, fluoranthene, fluorene, hexacene, hexaphene,
hexylene, as-indacene, s-indacene, indane, indene, naphthalene,
octacene, octaphene, octalene, ovalene, penta-2,4-diene, pentacene,
pentalene, pentaphene, perylene, phenalene, phenanthrene, picene,
pleiadene, pyrene, pyranthrene, rubicene, triphenylene,
trinaphthalene and the like.
[0059] "Aryl" by itself or as part of another substituent refers to
a monovalent aromatic hydrocarbon radical derived by the removal of
one hydrogen atom from a single carbon atom of a parent aromatic
ring system. Typical aryl groups include, but are not limited to,
groups derived from aceanthrylene, acenaphthylene,
acephenanthrylene, anthracene, azulene, benzene, chrysene,
coronene, fluoranthene, fluorene, hexacene, hexaphene, hexylene,
as-indacene, s-indacene, indane, indene, naphthalene, octacene,
octaphene, octalene, ovalene, penta-2,4-diene, pentacene,
pentalene, pentaphene, perylene, phenalene, phenanthrene, picene,
pleiadene, pyrene, pyranthrene, rubicene, triphenylene,
trinaphthalene and the like. In some embodiments, an aryl group is
from 6 to 20 carbon atoms. In other embodiments, an aryl group is
from 6 to 12 carbon atoms.
[0060] "Arylalkyl" by itself or as part of another substituent
refers to an acyclic alkyl radical in which one of the hydrogen
atoms bonded to a carbon atom, typically a terminal or sp3 carbon
atom, is replaced with an aryl group. Typical arylalkyl groups
include, but are not limited to, benzyl, 2-phenylethan-1-yl,
2-phenylethen-1-yl, naphthylmethyl, 2-naphthylethan-1-yl,
2-naphthylethen-1-yl, naphthobenzyl, 2-naphthophenylethan-1-yl and
the like. Where specific alkyl moieties are intended, the
nomenclature arylalkanyl, arylalkenyl and/or arylalkynyl is used.
In some embodiments, an arylalkyl group is (C.sub.6-C.sub.30)
arylalkyl, e.g., the alkanyl, alkenyl or alkynyl moiety of the
arylalkyl group is (C.sub.1-C.sub.10) and the aryl moiety is
(C.sub.6-C.sub.20). In other embodiments, an arylalkyl group is
(C.sub.6-C.sub.20) arylalkyl, e.g., the alkanyl, alkenyl or alkynyl
moiety of the arylalkyl group is (C.sub.1-C.sub.8) and the aryl
moiety is (C.sub.6-C.sub.12).
[0061] "Aryloxy" refers to a radical --C--O-aryl where aryl is as
defined herein.
[0062] "Aryloxycarbonyl" refers to a radical --C(O)--O-aryl where
aryl is as defined herein.
[0063] "Azide derivatives" as used herein refer to a compound or a
radical thereof having the structure N.dbd.N.dbd.N. The azide group
can be used as the point of attachment to a therapeutic or
targeting group, optionally via a linker. Examples of azide
derivatives include, but are not limited to,
2-hydroxy-3-azidopropyl methacrylate, 2-hydroxy-3-azidopropyl
acrylate, 3-azidopropyl methacrylate.
[0064] "Carbamoyl" by itself or as part of another substituent
refers to the radical --C(O)NR.sup.39R.sup.40 where R.sup.39 and
R.sup.40 are independently hydrogen, alkyl, cycloalkyl or aryl as
defined herein.
[0065] "Carbamoyloxy" by itself or as part of another substituent
refers to the radical --OC(O)NR.sup.41R.sup.42 where R.sup.41 and
R.sup.42 are independently hydrogen, alkyl, cycloalkyl or aryl as
defined herein.
[0066] "Carbazole derivatives" as used herein refer to a compound
or radical thereof having the structure
##STR00003##
and any substitutions at any site thereof. The carbazole group can
be used as the point of attachment to a therapeutic or targeting
group, optionally via a linker. Examples of carbazole derivatives
include but are not limited to, N-vinylcarbazole.
[0067] Carboxylate" refers to a compound or radical thereof having
the structure RCOO--, where R can be any desired substitutent.
[0068] "Compounds" include, but are not limited to, optical isomers
of compounds, racemates thereof, and other mixtures thereof. In
such embodiments, the single enantiomers or diastereomers, i.e.,
optically active forms, can be obtained by asymmetric synthesis or
by resolution of the racemates. Resolution of the racemates may be
accomplished, for example, by conventional methods such as
crystallization in the presence of a resolving agent, or
chromatography, using, for example a chiral high-pressure liquid
chromatography (HPLC) column. In addition, compounds can include Z-
and E-forms (or cis- and trans-forms) of compounds with double
bonds.
[0069] "Compounds" may also include isotopically labeled compounds
where one or more atoms have an atomic mass different from the
atomic mass conventionally found in nature. Examples of isotopes
that may be incorporated into the compounds disclosed herein
include, but are not limited to, .sup.2H, .sup.3H, .sup.11C,
.sup.13C.sub., .sup.14C, .sup.15N, .sup.18O, .sup.17O, etc.
Compounds may exist in unsolvated forms as well as solvated forms,
including hydrated forms and as N-oxides. In general, compounds as
referred to herein may be free acid, hydrated, solvated, or
N-oxides of a Formula. Certain compounds may exist in multiple
crystalline, co-crystalline, or amorphous forms. Compounds include
pharmaceutically acceptable salts thereof, or pharmaceutically
acceptable solvates of the free acid form of any of the foregoing,
as well as crystalline forms of any of the foregoing.
[0070] "Compounds" as defined by a chemical formula as disclosed
herein include any specific compounds within the formula. Compounds
may be identified either by their chemical structure and/or
chemical name. When the chemical structure and chemical name
conflict, the chemical structure is determinative of the identity
of the compound. The compounds described herein may comprise one or
more chiral centers and/or double bonds and therefore may exist as
stereoisomers such as double-bond isomers (i.e., geometric
isomers), enantiomers, or diastereomers. Accordingly, any chemical
structures within the scope of the specification depicted, in whole
or in part, with a relative configuration encompass all possible
enantiomers and stereoisomers of the illustrated compounds
including the stereoisomerically pure form (e.g., geometrically
pure, enantiomerically pure, or diastereomerically pure) and
enantiomeric and stereoisomeric mixtures. Enantiomeric and
stereoisomeric mixtures may be resolved into their component
enantiomers or stereoisomers using separation techniques or chiral
synthesis techniques well known to the skilled artisan.
[0071] "Conjugate acid of an organic base" refers to the protonated
form of a primary, secondary or tertiary amine or heteroaromatic
nitrogen base. Representative examples include, but are not limited
to, triethylammonium, morpholinium and pyridinium.
[0072] "Covalent grafting" as used herein refers to attaching a
polymer, polymer precursor, or small molecule by one or more
covalent bonds from a functional group to the surface of a
nanoparticle or by a delocalized bond complex, such as a
delocalized bond complex.
[0073] "Cyano derivatives" as used herein refer to compounds or
radicals thereof having the structure RCN. R can each independently
be any desired substituent. The cyano group can be used as the
point of attachment to a therapeutic or targeting group, optionally
via a linker. Examples of cyano derivatives include, but are not
limited to, 2-cyanoethyl acrylate.
[0074] "Cycloalkyl" by itself or as part of another substituent
refers to a saturated or unsaturated cyclic alkyl radical. Where a
specific level of saturation is intended, the nomenclature
"cycloalkanyl" or "cycloalkenyl" is used. Typical cycloalkyl groups
include, but are not limited to, groups derived from cyclopropane,
cyclobutane, cyclopentane, cyclohexane and the like. In some
embodiments, the cycloalkyl group is (C.sub.3-C.sub.10) cycloalkyl.
In other embodiments, the cycloalkyl group is (C.sub.3-C.sub.7)
cycloalkyl.
[0075] "Cycloheteroalkyl" by itself or as part of another
substituent refers to a saturated or unsaturated cyclic alkyl
radical in which one or more carbon atoms (and any associated
hydrogen atoms) are independently replaced with the same or
different heteroatom. Typical heteroatoms to replace the carbon
atom(s) include, but are not limited to, N, P, O, S, Si, etc. Where
a specific level of saturation is intended, the nomenclature
"cycloheteroalkanyl" or "cycloheteroalkenyl" is used. Typical
cycloheteroalkyl groups include, but are not limited to, groups
derived from epoxides, azirines, thiiranes, imidazolidine,
morpholine, piperazine, piperidine, pyrazolidine, pyrrolidine,
quinuclidine, and the like.
[0076] "Dialkylamino" by itself or as part of another substituent
refers to the radical --NR.sup.43R.sup.44 where R.sup.43 and
R.sup.44 are independently alkyl, cycloalkyl, cycloheteroalkyl,
arylalkyl, heteroalkyl or heteroarylalkyl, or optionally R.sup.43
and R.sup.44 together with the nitrogen to which they are attached
form a cycloheteroalkyl ring.
[0077] "Epoxide derivatives" as used herein refer to compounds or
radicals thereof having the following chemical structure:
##STR00004##
[0078] "Ester derivatives" as used herein refer to a compound or a
radical thereof having the generic chemical structure RC(O)OR'. R
and R' can each independently be any desired substituent. The ester
group can be used as the point of attachment to a therapeutic or
targeting group, optionally via a linker. Examples include, but are
not limited to, methyl acrylate, methyl methacrylate, tert-butyl
acrylate, tert-butyl methacrylate, vinyl acetate, benzyl acrylate
and benzyl methacrylate.
[0079] "Ether derivatives" as used herein refer to a compound or a
radical thereof having the generic chemical structure R--O--R'. The
ether group can be used as the point of attachment to a therapeutic
or targeting group, optionally via a linker. Examples include, but
are not limited to, methyl vinyl ether, butyl vinyl ether,
2-chloroethyl vinyl ether, cyclohexyl vinyl ether.
[0080] "Grafting" or "grafted onto" as used herein refers to
attaching a polymer, polymer precursor or small molecule to the
surface of a nanoparticle via a single functional group. Grafting
includes both covalent and non-covalent binding, as well as, but
not limited to, delocalized bond formation between one or more
atoms of the nanoparticle and one or more atoms of the functional
group, ionic bonding, hydrogen bonding, dipole-dipole bonding, and
van der Waals forces (for non-limiting examples see FIG. 1).
Formation of exemplary bonds are depicted in Schemes 2 and 3
described herein. The terms "grafting" and "grafting onto" include
methods conventionally referred to as grafting from and grafting
to.
[0081] "Halide derivatives" as used herein refer to compounds or
radicals thereof having a halide substituent. The halide group can
be used as the point of attachment to a therapeutic or targeting
group, optionally via a linker. Examples include, but are not
limited to, vinyl chloride, 3-chlorostyrene, 2,4,6-tribromophenyl
acrylate, 4-chlorophenyl acrylate, 2-bromoethyl acrylate.
Non-limiting examples include, but are not limited to,
divinylbenzene, ethylene glycol diacrylate, N,N-diallylacrylamide,
and allyl methacrylate.
[0082] "Halo" means fluoro, chloro, bromo, or iodo radical.
[0083] "Heteroalkyl, Heteroalkanyl, Heteroalkenyl and
Heteroalkynyl" by themselves or as part of another substituent
refer to alkyl, alkanyl, alkenyl and alkynyl groups, respectively,
in which one or more of the carbon atoms (and any associated
hydrogen atoms) are independently replaced with the same or
different heteroatomic groups. Typical heteroatomic groups which
can be included in these groups include, but are not limited to,
--O--, --S--, --O--O--, --S--S--, --O--S--, --NR.sup.45R.sup.46,
--.dbd.N--N.dbd.--, --N.dbd.N--, --N.dbd.N--NR.sup.47R.sup.48,
--PR.sup.49--, --P(O).sub.2--, --POR.sup.50--, --O--P(O).sub.2--,
--SO--, --SO.sub.2--, --SnR.sup.51R.sup.52-- and the like, where
R.sup.45, R.sup.46, R.sup.47, R.sup.48, R.sup.49, R.sup.50,
R.sup.51 and R.sup.52 are independently hydrogen, alkyl,
substituted alkyl, aryl, substituted aryl, arylalkyl, substituted
arylalkyl, cycloalkyl, substituted cycloalkyl, cycloheteroalkyl,
substituted cycloheteroalkyl, heteroalkyl, substituted heteroalkyl,
heteroaryl, substituted heteroaryl, heteroarylalkyl or substituted
heteroarylalkyl.
[0084] "Heteroalkyloxy" means an --O-heteroalkyl where heteroalkyl
is as defined herein.
[0085] "Heteroaromatic Ring System" by itself or as part of another
substituent refers to an aromatic ring system in which one or more
carbon atoms (and any associated hydrogen atoms) are independently
replaced with the same or different heteroatom. Typical heteroatoms
to replace the carbon atoms include, but are not limited to, N, P,
O, S, Si, etc. Specifically included within the definition of
"heteroaromatic ring systems" are fused ring systems in which one
or more of the rings are aromatic and one or more of the rings are
saturated or unsaturated, such as, for example, arsindole,
benzodioxan, benzofuran, chromane, chromene, indole, indoline,
xanthene, etc. Typical heteroaromatic ring systems include, but are
not limited to, arsindole, carbazole, .beta.-carboline, chromane,
chromene, cinnoline, furan, imidazole, indazole, indole, indoline,
indolizine, isobenzofuran, isochromene, isoindole, isoindoline,
isoquinoline, isothiazole, isoxazole, naphthyridine, oxadiazole,
oxazole, perimidine, phenanthridine, phenanthroline, phenazine,
phthalazine, pteridine, purine, pyran, pyrazine, pyrazole,
pyridazine, pyridine, pyrimidine, pyrrole, pyrrolizine,
quinazoline, quinoline, quinolizine, quinoxaline, tetrazole,
thiadiazole, thiazole, thiophene, triazole, xanthene, and the
like.
[0086] "Heteroaryl" by itself or as part of another substituent
refers to a monovalent heteroaromatic radical derived by the
removal of one hydrogen atom from a single atom of a parent
heteroaromatic ring system. Typical heteroaryl groups include, but
are not limited to, groups derived from acridine, arsindole,
carbazole, .beta.-carboline, chromane, chromene, cinnoline, furan,
imidazole, indazole, indole, indoline, indolizine, isobenzofuran,
isochromene, isoindole, isoindoline, isoquinoline, isothiazole,
isoxazole, naphthyridine, oxadiazole, oxazole, perimidine,
phenanthridine, phenanthroline, phenazine, phthalazine, pteridine,
purine, pyran, pyrazine, pyrazole, pyridazine, pyridine,
pyrimidine, pyrrole, pyrrolizine, quinazoline, quinoline,
quinolizine, quinoxaline, tetrazole, thiadiazole, thiazole,
thiophene, triazole, xanthene, and the like. Preferably, the
heteroaryl group is from 5-20 membered heteroaryl, more preferably
from 5-10 membered heteroaryl. Certain heteroaryl groups are those
derived from thiophene, pyrrole, benzothiophene, benzofuran,
indole, pyridine, quinoline, imidazole, oxazole and pyrazine.
[0087] "Heteroarylalkyl" by itself or as part of another
substituent refers to an acyclic alkyl radical in which one of the
hydrogen atoms bonded to a carbon atom, typically a terminal or sp3
carbon atom, is replaced with a heteroaryl group. Where specific
alkyl moieties are intended, the nomenclature heteroarylalkanyl,
heteroarylalkenyl and/or heterorylalkynyl is used. In some
embodiments, the heteroarylalkyl group is a 6-30 membered
heteroarylalkyl, e.g., the alkanyl, alkenyl or alkynyl moiety of
the heteroarylalkyl is 1-10 membered and the heteroaryl moiety is a
5-20-membered heteroaryl. In other embodiments, the heteroarylalkyl
group is a 6-20 membered heteroarylalkyl, e.g., the alkanyl,
alkenyl or alkynyl moiety of the heteroarylalkyl is 1-8 membered
and the heteroaryl moiety is a 5-12-membered heteroaryl.
[0088] "Heteroaryloxycarbonyl" refers to a radical --C(O)--OR where
R is heteroaryl as defined herein.
[0089] "Hydroxyl derivative" as used herein refers to a compound or
radical having the structure ROH. The deprotonated hydroxyl group
can be used as the point of attachment to a therapeutic or
targeting group, optionally via a linker. Example of hydroxyl
derivatives include, but are not limited to, vinyl alcohol,
2-hydroxyethyl acrylate, 2-hydroxyethyl methacrylate,
2-allyl-2-methoxyphenol, divinyl glycol, glycerol monomethacrylate,
poly(propylene glycol) monomethacrylate,
N-(2-hydroxypropyl)methacrylamide,
hydroxymethyldiacetoneacrylamide, poly(ethylene glycol)
monomethacrylate, N-methacryloylglycylglycine,
N-methacryloylglycyl-DL-phenylalanylleucylglycine,
4-methacryloxy-2-hydroxybenzophenone, 1,1,1-trimethylolpropane
diallyl ether, 4-allyl-2-methoxyphenol,
hydroxymethyldiacetoneacrylamide, N-methylolacrylamide, and sugar
based monomers.
[0090] "Maleimide derivative" as referred to herein refers to a
compound or a radical thereof having the structure:
##STR00005##
[0091] "Morpholine derivatives" as used herein refer to compounds
or radicals thereof having the structure:
##STR00006##
Typically, the amine group serves as the point of attachment to
other compounds. The morpholine group can be used as the point of
attachment to a therapeutic or targeting group, optionally via a
linker. Examples of morpholine derivatives include, but are not
limited to, N-acryloylmorpholine, 2-N-morpholinoethyl acrylate and
2-N-morpholinoethyl methacrylate.
[0092] "Nitro derivatives" as used herein refer to compounds or
radicals thereof having an NO2 group. The nitro group can be used
as the point of attachment to a therapeutic or targeting group,
optionally via a linker. Examples include, but are not limited to,
o-nitrobenzyl methacrylate,
methacryloylglycyl-DL-phenylalanyl-L-leucyl-glycine 4-nitrophenyl
ester, methacryloylglycyl-L-phenylalanyl-L-leucyl-glycine
4-nitrophenyl ester, N-methacryloylglycylglycine 4-nitrophenyl
ester, 4-nitrostyrene
[0093] "Patient" includes animals and mammals, such as for example,
humans.
[0094] "Pharmaceutical composition" refers to a compound or
nanoparticle at least one pharmaceutically acceptable vehicle, with
which the compound or nanoparticle is administered to a patient
[0095] "Pharmaceutically acceptable salt" refers to a salt of a
compound, which possesses the desired pharmacological activity of
the parent compound. Such salts include acid addition salts, formed
with inorganic acids such as hydrochloric acid, hydrobromic acid,
sulfuric acid, nitric acid, phosphoric acid, and the like; or
formed with organic acids such as acetic acid, propionic acid,
hexanoic acid, cyclopentanepropionic acid, glycolic acid, pyruvic
acid, lactic acid, malonic acid, succinic acid, malic acid, maleic
acid, fumaric acid, tartaric acid, citric acid, benzoic acid,
3-(4-hydroxybenzoyl)benzoic acid, cinnamic acid, mandelic acid,
methanesulfonic acid, ethanesulfonic acid, 1,2-ethane-disulfonic
acid, 2-hydroxyethanesulfonic acid, benzenesulfonic acid,
4-chlorobenzenesulfonic acid, 2-naphthalenesulfonic acid,
4-toluenesulfonic acid, camphorsulfonic acid,
4-methylbicyclo[2.2.2]-oct-2-ene-1-carboxylic acid, glucoheptonic
acid, 3-phenylpropionic acid, trimethylacetic acid, tertiary
butylacetic acid, lauryl sulfuric acid, gluconic acid, glutamic
acid, hydroxynaphthoic acid, salicylic acid, stearic acid, muconic
acid, and the like; and salts formed when an acidic proton present
in the parent compound is replaced by a metal ion, e.g., an alkali
metal ion, an alkaline earth ion, or an aluminum ion; or
coordinates with an organic base such as ethanolamine,
diethanolamine, triethanolamine, N-methylglucamine, and the like.
In certain embodiments, a pharmaceutically acceptable salt is the
hydrochloride salt. In certain embodiments, a pharmaceutically
acceptable salt is the sodium salt.
[0096] "Pharmaceutically acceptable vehicle" refers to a
pharmaceutically acceptable diluent, a pharmaceutically acceptable
adjuvant, a pharmaceutically acceptable excipient, a
pharmaceutically acceptable carrier, or a combination of any of the
foregoing with which a compound provided by the present disclosure
may be administered to a patient and which does not destroy the
pharmacological activity thereof and which is non-toxic when
administered in doses sufficient to provide a therapeutically
effective amount of the compound. "Phosphate derivatives" as used
herein refer to compounds or radicals thereof having at least one
compound containing the structure RR'R''PO.sub.4. R, R' and R'' can
each independently be any desired substituent, including but not
limited to hydrogen, alkyl, alkoxy, aryl or acyl groups. The
phosphate group can be used as the point of attachment to a
therapeutic or targeting group, optionally via a linker. Examples
of phosphate derivatives include, but are not limited to,
monoacryloxyethyl phosphate and bis(2-methacryloxyethyl)
phosphate.
[0097] "Phosphinate" refers to a compound or radical thereof having
the structure OP(OR)R'R'' where R, R' and R' can each independently
be any desired substituent.
[0098] "Phosphonate" refers to a compound or radical thereof having
the structure R--PO(OH).sub.2 or R--PO(OR').sub.2. where R and R'
can each independently be any desired substituent.
[0099] "R, R' and R'' can each independently be any desired
substituent.
[0100] "R, R', R'', and R''' can each independently be any desired
substituent. The epoxide group can be used as the point of
attachment to a therapeutic or targeting group, optionally via a
linker. Examples of epoxide derivatives include, but are not
limited to, glycidyl methacrylate.
[0101] "Reducing agent" is an element or a compound that reduces
another species. Exemplary reducing agents include, but are not
limited to, ferrous ion, lithium aluminium hydride (LAIN, potassium
ferricyanide (K.sub.3Fe(CN).sub.6), sodium borohydride
(NaBH.sub.4), sulfites, hydrazine, diisobutylaluminum hydride
(DIBAH), primary amines, and oxalic acid
(C.sub.2H.sub.2O.sub.4).
[0102] "Salt" refers to a salt of a compound, including, but not
limited to, pharmaceutically acceptable salts.
[0103] "Silane derivative" as used herein refers to compounds or
radicals thereof having at least one substituent having the
structure RSiR'R''R'''. R, R' and R'' can each independently be any
desired substituent, including but not limited to hydrogen, alkyl,
alkoxy, aryl or acyl groups. The silane group can be used as the
point of attachment to a therapeutic or targeting group, optionally
via a linker. Examples of silane derivatives include, but are not
limited to, 3-methacryloxypropyl trimethoxysilane,
vinyltriethoxysilane, 2-(trimethylsiloxy)ethyl methacrylate,
1-(2-trimethylsiloxyethoxy)-1-trimethylsiloxy-2-methylpropene
[0104] "Solvate" refers to a molecular complex of a compound with
one or more solvent molecules in a stoichiometric or
non-stoichiometric amount. Such solvent molecules are those
commonly used in the pharmaceutical art, which are known to be
innocuous to a patient, e.g., water, ethanol, and the like. A
molecular complex of a compound or moiety of a compound and a
solvent can be stabilized by non-covalent intra-molecular forces
such as, for example, electrostatic forces, van der Waals forces,
or hydrogen bonds. The term "hydrate" refers to a solvate in which
the one or more solvent molecules is water.
[0105] "Substituted" refers to a group in which one or more
hydrogen atoms are each independently replaced with the same or
different substituent(s). Typical substituents include, but are not
limited to, --X, --R.sup.29, --O--, .dbd.O, --OR'', --SR'', --S--,
.dbd.S, --NR.sup.29R.sup.30, .dbd.NR'', --CX.sub.3, --CF.sub.3,
--CN, --OCN, --SCN, --NO, --NO.sub.2, .dbd.N.sub.2, --N.sub.3,
--S(O).sub.2O--, --S(O).sub.2OH, --S(O).sub.2R.sup.29,
--OS(O.sub.2)O--, --OS(O).sub.2R.sup.29, --P(O)(O--).sub.2,
--P(O)(OR.sup.29)(O--), --OP(O)(OR.sup.29)(OR.sup.30),
--C(O)R.sup.29, --C(S)R.sup.29, --C(O)OR.sup.29,
--C(O)NR.sup.29R.sup.30, --C(O)O--, --C(S)OR.sup.29,
--NR.sup.31C(O)NR.sup.29R.sup.30, --NR.sup.31C(S)NR.sup.29R.sup.30,
--NR.sup.31C(NR.sup.29)NR.sup.29R.sup.30 and
--C(NR.sup.29)NR.sup.29R.sup.30, where each X is independently a
halogen; each R.sup.29 and R.sup.30 are independently hydrogen,
alkyl, substituted alkyl, aryl, substituted aryl, arylalkyl,
substituted arylalkyl, cycloalkyl, substituted cycloalkyl,
cycloheteroalkyl, substituted cycloheteroalkyl, heteroalkyl,
substituted heteroalkyl, heteroaryl, substituted heteroaryl,
heteroarylalkyl, substituted heteroarylalkyl, --NR.sup.31R.sup.32,
--C(O)R.sup.31 or --S(O).sub.2R.sup.31 or optionally R.sup.29 and
R.sup.30 together with the atom to which they are both attached
form a cycloheteroalkyl or substituted cycloheteroalkyl ring; and
R.sup.31 and R.sup.32 are independently hydrogen, alkyl,
substituted alkyl, aryl, substituted aryl, arylalkyl, substituted
arylalkyl, cycloalkyl, substituted cycloalkyl, cycloheteroalkyl,
substituted cycloheteroalkyl, heteroalkyl, substituted heteroalkyl,
heteroaryl, substituted heteroaryl, heteroarylalkyl or substituted
heteroarylalkyl.
[0106] "Succinimide derivative" as used herein refers to compounds
or radicals thereof having the group
##STR00007##
[0107] The succinyl R groups can be substituted by any substituent,
for example and substituted or unsubstituted alkyl, alcoxy, aryl
groups. Typically, the succinimide group is attached to a compound
via a covalent bond at the nitrogen. The succinimide group can be
used as the point of attachment to a therapeutic or targeting
group, optionally via a linker. A succinimide derivative can be a
sulfo-containing succinimide derivative. N-acryloxysuccinimide is
an exemplary succinimide derivative.
[0108] "Sulfonamido" by itself or as part of another substituent
refers to a radical --NR.sup.53S(O).sub.2R.sup.54, where R.sup.53
is alkyl, substituted alkyl, cycloalkyl, cycloheteroalkyl, aryl,
substituted aryl, arylalkyl, heteroalkyl, heteroaryl or
heteroarylalkyl and R.sup.54 is hydrogen, alkyl, cycloalkyl,
cycloheteroalkyl, aryl, arylalkyl, heteroalkyl, heteroaryl or
heteroarylalkyl as defined herein. Representative examples include,
but are not limited to methanesulfonamido, benzenesulfonamido and
p-toluenesulfonamido.
[0109] "Sulfonic acids derivatives" as used herein are a class of
organic acid radicals with the general formula RSO.sub.3H or
RSO.sub.3. An oxygen, suflur, or R moiety can serve as a point of
attachment. Sulfonic acid salt derivatives substitute a cationic
salt (e.g. Na.sup.+, K.sup.+, etc.) for the hydrogen on the sulfate
group. In various embodiments, the deprotonated sulfonic acid group
can be used as the point of attachment to a therapeutic or
targeting group, optionally via a linker. Examples of sulfonic acid
derivatives and include, but are not limited to,
2-methyl-2-propane-1-sulfonic acid--sodium salt, 2-sulfoethyl
methacrylate, 3-phenyl-1-propene-2-sulfonic acid--p-toluidine salt,
3-sulfopropyl acrylate--potassium salt, 3-sulfopropyl
methacrylate--potassium salt, ammonium 2-sulfatoethyl methacrylate,
styrene sulfonic acid, 4-sodium styrene sulfonate.
[0110] "Sulphate" refers to a compound or radical thereof having
the structure RSO.sub.4. where R can be any desired
substituent.
[0111] "Sulphonate" refers to a compound or radical thereof having
the structure RSO.sub.2O--where R can be any desired
substituent.
[0112] "Therapeutically effective amount" or "effective amount"
refers to the amount of a compound that, when administered to a
subject for treating a disease or disorder, or at least one of the
clinical symptoms of a disease or disorder, is sufficient to affect
such treatment of the disease, disorder, or symptom. The
"therapeutically effective amount" can vary depending, for example,
on the compound, the disease, disorder, and/or symptoms of the
disease or disorder, severity of the disease, disorder, and/or
symptoms of the disease or disorder, the age, weight, and/or health
of the patient to be treated, and the judgment of the prescribing
physician. An appropriate therapeutically effective amount in any
given instance may be ascertained by those skilled in the art or
capable of determination by routine experimentation.
[0113] "Therapeutically effective dose" or "effective dose" refers
to a dose of a drug, prodrug or active metabolite of a prodrug that
provides effective treatment of a disease or disorder in a patient.
A therapeutically effective dose may vary from compound to compound
and from patient to patient, and may depend upon factors such as
the condition of the patient and the route of delivery. A
therapeutically effective dose may be determined in accordance with
routine pharmacological procedures known to those skilled in the
art.
[0114] "Thioester" refers to a compound or radical thereof having
the structure R--S--CO--R', where R and R' can each independently
be any desired substituent.
[0115] "Thioether" refers to a compound or radical thereof having
the structure R--S--CO--R', where R and R' can each independently
be any desired substituent.
[0116] "Thiolate" refers to a compound or radical thereof having a
--SR structure, where R can be any desired substituent.
[0117] "Treating" or "treatment" of any disease or disorder refers
to arresting or ameliorating a disease, disorder, or at least one
of the clinical symptoms of a disease or disorder, reducing the
risk of acquiring a disease, disorder, or at least one of the
clinical symptoms of a disease or disorder, reducing the
development of a disease, disorder or at least one of the clinical
symptoms of the disease or disorder, or reducing the risk of
developing a disease, disorder, or at least one of the clinical
symptoms of a disease or disorder. "Treating" or "treatment" also
refers to inhibiting the disease, disorder, or at least one of the
clinical symptoms of a disease or disorder, either physically,
(e.g., stabilization of a discernible symptom), physiologically,
(e.g., stabilization of a physical parameter), or both, and to
inhibiting at least one physical parameter which may or may not be
discernible to the patient. In certain embodiments, "treating" or
"treatment" refers to delaying the onset of the disease or disorder
or at least one or more symptoms thereof in a patient which may be
exposed to or predisposed to a disease or disorder even though that
patient does not yet experience or display symptoms of the disease
or disorder. Nanoparticles
[0118] The present disclosure is directed to modified
gold/lanthanide nanoparticles, particularity gold/gadolinium
nanoparticles. The term "nanoparticle" as referred to herein means
a particle having at least one special dimension measurable less
than a micron in length. Nanoparticles include conventionally known
nanoparticles such as nanorods, nanospheres and nanoplatelets. In
various embodiments, for example, nanospheres can be a rod, sphere,
or any other three dimensional shape. Nanoparticles are generally
described, for example, in Burda et al., Chem. Rev. 2005, 105,
1025-1102.
[0119] The nanoparticles described herein are generally described
as gold/lanthanide nanoparticles, such as gold/gadolinium
nanoparticles. However, the descriptions provided herein may be
applied equally and fully to other lanthanide nanoparticles. In
this context, lanthanides include gadolinium, lanthanum, erbium,
ytterbium, neodymium, europium, terbium, cerium, thulium,
praseodymium, promethium, samarium, dysprosium, holmium, and
lutetium.
Gold Nanoparticles
[0120] Gold nanoparticles have architectures which provide tunable
optical properties. In various embodiments, gold nanoparticles are
configured for optical imaging techniques. For example, the optical
and electronic properties can be controlled by controlling the size
of the nanoparticle, varying the aspect ratio, or rationally
assembling nanoparticles into a specific shape. Those of skill in
the art will understand that the size of the gold nanoparticle can
be designed to have specific properties for different applications.
For example, the size of the gold nanoparticle can be designed for
colorimeric detection, as described in Martin and Mitchell, Anal.
Chem. 1998 pp. 332. Additionally, due to their tunable optical
properties, multifunctional polymer modified gold and
ultrasensitive surface-enhanced Raman detection of biomolecules
such as DNA and cancer markers. Metallic gold nanoparticles with
surface plasmon behavior have been used as unique optical probes
for colorimetric sensing and ultrasensitive surface-enhanced Raman
detection of biomolecules such as DNA and cancer markers. Cheon, J.
and Lee, Jae-Hyun, Synergistically Integrated Nanoparticles as
Multimodal Probes for Nanobiotechnology, Accounts of Chem. Res.,
published online at www.pubs.acs.org/acr on Aug. 13, 2008.
[0121] Gold nanoparticles may be prepared by methods known in the
art, including those disclosed by Burda et al., Chem. Rev. 2005,
105, 1025-1102 and Daniel and Astruc Chem. Rev. 2004, 104, 293-346.
Growth methods, including the template, electrochemical, or seeded
growth methods, are disclosed by Perez-Juste et al., Coordination
Chemistry Reviews 249 (2005) 1870-1901. Seed particle methods are
further described in Murphy et al. J. Phys. Chem. B 2005, 109,
13857-13870. Gold nanoparticles can also be prepared to have
specific surface structures by citrate reduction, two phage
synthesis and thiol stabilization, sulfur stabilization, and
stabilization with other ligands as described by Daniel and Astruc,
Chem. Rev. 2004, 104, 293-346.
Gadolinium Metal Organic Framework
[0122] Gadolinium (III) functions as a MRI contrast agent.
Gadolinium enhances the image contrast by increasing water proton
relaxation rates. When conjugated to targeting agents, gadolinium
metal organic frameworks are effective site-specific MRI contrast
agents owing to their large metal payload.
[0123] "Gadolinium metal organic framework" as used herein refers
to a metal organic framework containing gadolinium (III) Gd.sup.3+.
Gadolinium metal organic frameworks include, but are not limited
to, gadolinium (III) metal-organic frameworks such as those
containing carboxylic acids, ligands, and polymers. Representative
examples of gadolinium (III) metal organic frameworks include
Gd(1,4-benzenedicarboxylate)1.5(H.sub.2O).sub.2 (also known as
Gd(1,4-BDC)1.5(H.sub.2O).sub.2), Gd.sub.2O.sub.3, gadolinium
nitrate and emulsions thereof, and gadolinium fluoride.
[0124] Gadolinium metal organic frameworks can be synthesized by
any method known in the art. In a certain embodiment, the
gadolinium particles are synthesized as described in, e.g., Rieter,
W. J.; et al. J. Am. Chem. Soc. 2006, 128, 9024-9025. The quantity
of gadolinium (III) in gadolinium metal organic frameworks can be
controlled as described in the art by controlling reaction
conditions. Rieter, W. J. et al., J. Am. Chem. Soc. 2006 128,
9024-9025.
[0125] In alternative embodiments, gadolinium nanoparticles can be
synthesized to have a shell morphology with a functionalized
polymer on the surface. For example, gadolinium nanoparticles
having a paramagnetic Gd.sub.2O.sub.3 core can be produced by
encapsulating Gd.sub.2O.sub.3 cores within a polysiloxane shell
which carries organic fluorophores and carboxylated PEG covalently
tethered to the inorganic network as described in Bridot et al., J.
Am. Chem. Soc; (Article); 2007; 129(16); 5076-5084. In other
embodiments, the gadolinium nanoparticles can be synthesized as
inorganic/organic hybrid molecules, as described in Hifumi et al.
J. Am. Chem. Soc., 128 (47), 15090-15091, 2006.
[0126] The quantity of gadolinium in a gadolinium metal organic
framework can be modified to adjust contrast in MRI techniques. For
example, the quantity of gadolinium in a gadolinium nanoparticle
can be optimized for imaging techniques such as magnetic resonance
imaging (MRI). The quantity of gadolinium nanoparticles can be
adjusted for, for example, in Ahrens et al., Proc. Nat'l. Acad.
Sci. 95(15) 8443-8448 (1998). Various parameters of gadolinium
nanoparticles can be modified. Parameters include the concentration
of gadolinium (III), size, aspect ratio, and surface-to-volume
concentration of gadolinium (III) in the nanoparticle as described
in e.g. Rieter, W. J. et al., J. Am. Chem. Soc. 2006 128,
9024-9025.
Gadolinium Coated Gold Nanoparticles
[0127] A gadolinium organic framework is deposited on the gold
nanoparticle. The metal organic framework may be attached to the
gold nanoparticle via covalent, noncovalent, ionic, Van der Waals,
or other types of bonds.
[0128] A reverse microemulsion reaction is used to coat gold
nanoparticles with gadolinium metal organic frameworks (NMOF). In
one embodiment two aqueous solutions are prepared, one of
GdCl.sub.3 (0.5M) and the other containing 1,4-benzenedicarboxylic
acid (1,4-BDC) (0.075M). Next, the GdCl.sub.3 and 1,4-BDC aqueous
solutions are combined into a
heptane/hexanol/cetyltrimethylammonium bromide (0.05M)
microemulsion. Gold nanoparticles are then added to the solution
and the reaction is stirred vigorously for 24 hours at room
temperature. The nanoparticles are washed several times in ethanol
and finally stored in water.
[0129] A polymer may be affixed to the metal organic framework. The
polymer coating may be created either by polymerizing monomers from
the surface of the metal organic framework, or by first
polymerizing monomers and then attaching the resulting polymers to
the metal organic framework (FIG. 1).
[0130] The polymer coating may be added directly to the metal
organic framework via a a polymer precursor, or through an
initiator, formed by creating imperfections on the metal organic
framework.
Forming Initiators on the Nanoparticle Surface
[0131] Prior to growing polymers on the surface of gadolinium
coated gold nanoparticles, the nanoparticle can be treated to form
imperfections (or initiators) on the gadolinium metal organic
framework surface. In various embodiments, initiators facilitate
polymer formation or polymer precursor binding.
Polymerization
[0132] Polymerization can be performed by any method known in the
art. Polymerization methods that can be used are described in
Principles of Polymerization, 4th edition (2004) by George Odian,
Published by Wiley-Interscience, which is incorporated herein by
reference in its entirety. Various methods of polymerization
include RAFT, Atom Transfer Radical Polymerization (ATRP), Stable
Free Radical Polymerization (SFRP), and conventional free radical
polymerization.
[0133] Reversible addition-fragmentation chain transfer (RAFT)
polymerization operates on the principle of degenerative chain
transfer. Without being limited to a particular mechanism, Scheme 1
shows a proposed mechanism for RAFT polymerization. In Scheme 1,
RAFT polymerization involves a single- or multi-functional chain
transfer agent (CTA), such as the compound of formula (I),
including dithioesters, trithiocarbonates, xanthates, and
dithiocarbamates. The initiator produces a free radical, which
subsequently reacts with a polymerizable monomer. The monomer
radical reacts with other monomers and propagates to form a chain,
Pn*, which can react with the CTA. The CTA can fragment, either
forming R*, which will react with another monomer that will form a
new chain Pm* or Pn*, which will continue to propagate. In theory,
propagation to the Pm* and Pn* will continue until no monomer is
left or a termination step occurs. After the first polymerization
has finished, in particular circumstances, a second monomer can be
added to the system to form a block copolymer.
##STR00008##
[0134] RAFT polymerization involves a similar mechanism as
traditional free radical polymerization systems, with the
difference of a purposely added CTA. Addition of a growing chain to
a macro-CTA yields an intermediate radical, which can fragment to
either the initial reactants or a new active chain. With a high
chain transfer constant and the addition of a high concentration of
CTA relative to conventional initiator, synthesis of polymer with a
high degree of chain-end functionality and with well defined
molecular weight properties is obtained.
[0135] In particular embodiments, RAFT polymerization is used to
produce a variety of well-defined, novel polymers that either are
polymerized from the surface of the metal organic framework, or are
polymerized and then attached to the metal organic framework. RAFT
polymerization shows great promise in the synthesis of
multifunctional polymers due to the versatility of monomer
selection and polymerization conditions, along with the ability to
produce well-defined, narrow polydispersity polymers with both
simple and complex architectures.
[0136] In particular embodiments, RAFT polymerization is used to
produce a variety of well-defined, novel biocopolymers as
constructs for multifunctional systems for the surface modification
of nanoparticles consisting of gold nanoparticles coated in a metal
organic framework (MOF) of gadolinium. The inherent flexibility of
RAFT polymerizations makes it a candidate to produce well-defined
polymer structures with a high degree of functionality capable of
providing increased therapeutic/targeting agent loading and loading
efficiency.
[0137] For example, RAFT can be successfully used to produce
well-defined activated biocopolymer constructs with
N-acryloxysuccinimide (NAOS) pendant functionalities. The
succinimide side groups have allowed covalent conjugation of
bioactive agents such as fluorescent tags, nucleotides, peptides,
and antibodies. R. P. Sebra, Langmuir 2005, 21, 10907-10911; M. J.
Yanjarappa, Biomacromolecules 2006, 7, 1665-1670. Incorporation of
NAOS into copolymers provides a route of manipulating loading
efficiency and stability of bioactive agents. Additional tailoring
of the copolymer conjugate system with tumor targeting or
therapeutic agents allows specific localization and treatment to be
achieved increasing in vivo performance.
[0138] Polymers synthesized by RAFT include chain transfer agents
(CTAs). As used herein, a RAFT chain transfer agent is defined as
having the chemical structure of Formula (IV):
##STR00009##
[0139] CTAs agents possessing the thiocarbonylthio moiety, impart
reactivity to free-radical polymerization due to the facile nature
of radical addition to C.dbd.S bonds which contributes to faster
chain equilibration in the chain transfer step. The transfer
constants of RAFT CTAs depend on the Z and R substituents. In
certain embodiments, the Z group is a free radical stabilizing
species to ensure rapid addition across the C.dbd.S bond.
[0140] In certain embodiments, the R group is chosen so that it
possesses an equal or greater ability to leave as compared to the
addition species. It is also of importance that the R group be able
to reinitiate the polymerization after fragmentation. In certain
embodiments, R can fragment from the intermediate quickly and is
able to re-initiate polymerization effectively.
[0141] Exemplary CTAs include, but are not limited to, cumyl
dithiobenzoate (CDTB) and
S-1-Dodecyl-S'-(.alpha.,.alpha.'-dimethyl-.alpha.''-acetic acid)
trithiocarbonate (DATC).
[0142] Grafting Polymers and Polymer Precursors to
Nanoparticles
[0143] In certain aspects, polymers can be grafted to the
gadolinium metal organic framework after polymerization. Optimal
choice of CTA structures of formula (I) allows for control of the
polymerization. The Z group activates the thio-carbonyl (C.dbd.S)
group for radical addition and allows for the radical intermediate
to be stabilized in the transition state.
[0144] Schemes 2 and 3 show grafting trithiocarbonate and
dithioester RAFT agents to the surface of a gadolinium
nanoparticle. Scheme 2 shows first RAFT polymerization of the
alkene in the presence of the trithiocarbonate, and Scheme 3 shows
a first step of RAFT polymerization of the alkene in the presence
of the dithioester.
[0145] The RAFT polymer is grafted to the surface of the
nanoparticle. Without being limited to any particular mechanism,
the nanoparticle is covalently grafted to the nanoparticle surface.
The reduced polymer is covalently grafted to the nanoparticle.
##STR00010##
##STR00011##
[0146] In Schemes 2 and 3, R.sub.1, R.sub.2, R.sub.3, and R.sub.4
are each independently selected from hydrogen, alkyl, substituted
alkyl, alkoxy, substituted alkoxy, acyl, substituted acyl,
acylamino, substituted acylamino, alkylamino, substituted
alkylamino, alkylsulfinyl, substituted alkylsulfinyl,
alkylsulfonyl, substituted alkylsulfonyl, alkylthio, substituted
alkylthio, alkoxycarbonyl, substituted alkoxycarbonyl, aryl,
substituted aryl, arylalkyl, substituted arylalkyl, aryloxy,
substituted aryloxy, aryloxycarbonyl, substituted aryloxycarbonyl,
carbamoyl, substituted carbamoyl, cycloalkyl, substituted
cycloalkyl, cycloheteroalkyl, substituted cycloheteroalkyl,
dialkylamino, substituted dialkylamino, halo, heteroalkyl,
substituted heteroalkyl, heteroaryl, substituted heteroaryl,
heteroarylalkyl, substituted heteroarylalkyl, heteroalkyloxy,
substituted heteroalkyloxy, heteroaryloxy and substituted
heteroaryloxy.
[0147] A specific example of RAFT polymers attached to the surface
of the gadolinium particle after polymerization is depicted in
Scheme 4 below.
[0148] The modified polymer can be added to the gadolinium
nanoparticle after reduction of the trithiocarbonate group to a
thiol to produce a gadolinium nanoparticle conjugate. Scheme 4
depicts a method of attaching a modified polymer to a gadolinium
nanoparticle to produce a gadolinium nanoparticle conjugate.
##STR00012##
Grafting From Nanoparticles
[0149] In the two examples of generalized RAFT polymerization
described above in Schemes 2 and 3, as well as the specific example
in Scheme 4, polymerization occurs prior to grafting to the
gadolinium nanoparticle surfaces (i.e. "grafting to" the
nanoparticle surface).
[0150] Alternatively, the RAFT polymerization may be accomplished
after grafting a polymer precursor, initiator, or CTA to the
nanoparticle surface. Scheme 5 depicts attachment of a CTA to a
surface-bound RAFT polymerization. In brief, a polymer precursor is
grafted to the surface of the nanoparticle. A CTA is attached to
the terminus of the polymer precursor in Step 1. RAFT
polymerization is then accomplished in Step 2 directly from the
surface of the gadolinium nanoparticle, as described, for example,
in Rowe-Konopacki, M. D. and Boyes, S. G. Synthesis of Surface
Initiated Diblock Copolymer Brushes from Flat Silicon Substrates
Utilizing the RAFT Polymerization Technique. Macromolecules, 40 (4)
879-888, 2007, and Rowe, M. D.; Hammer, B. A. G.; Boyes, S. G.
Synthesis of Surface-Initiated Stimuli-Responsive Diblock Copolymer
Brushes Utilizing a Combination of ATRP and RAFT Polymerization
Techniques. Macromolecules, 41 (12), 4147-4157, 2008.
##STR00013##
[0151] In Scheme 5, n is an integer, and X, R, R.sub.1, R.sub.2,
R.sub.3 and R.sub.4 are each independently selected from hydrogen,
alkyl, substituted alkyl, alkoxy, substituted alkoxy, acyl,
substituted acyl, acylamino, substituted acylamino, alkylamino,
substituted alkylamino, alkylsulfinyl, substituted alkylsulfinyl,
alkylsulfonyl, substituted alkylsulfonyl, alkylthio, substituted
alkylthio, alkoxycarbonyl, substituted alkoxycarbonyl, aryl,
substituted aryl, arylalkyl, substituted arylalkyl, aryloxy,
substituted aryloxy, carbamoyl, substituted carbamoyl, cycloalkyl,
substituted cycloalkyl, cycloheteroalkyl, substituted
cycloheteroalkyl, dialkylamino, substituted dialkylamino, halo,
heteroalkyl, substituted heteroalkyl, heteroaryl, substituted
heteroaryl, heteroarylalkyl, substituted heteroarylalkyl,
heteroalkyloxy, substituted heteroalkyloxy, heteroaryloxy and
substituted heteroaryloxy. In certain embodiments, X is a halide
such as fluorine, bromine, chlorine and iodine. A specific example
of the reaction of Scheme 5 is depicted in Scheme 6.
##STR00014##
[0152] R.sub.3 and R.sub.4 are each independently selected from
hydrogen, alkyl, substituted alkyl, alkoxy, substituted alkoxy,
acyl, substituted acyl, acylamino, substituted acylamino,
alkylamino, substituted alkylamino, alkylsulfinyl, substituted
alkylsulfinyl, alkylsulfonyl, substituted alkylsulfonyl, alkylthio,
substituted alkylthio, alkoxycarbonyl, substituted alkoxycarbonyl,
aryl, substituted aryl, arylalkyl, substituted arylalkyl, aryloxy,
substituted aryloxy, aryloxycarbonyl, substituted aryloxycarbonyl,
carbamoyl, substituted carbamoyl, cycloalkyl, substituted
cycloalkyl, cycloheteroalkyl, substituted cycloheteroalkyl,
dialkylamino, substituted dialkylamino, halo, heteroalkyl,
substituted heteroalkyl, heteroaryl, substituted heteroaryl,
heteroarylalkyl, substituted heteroarylalkyl, heteroalkyloxy,
substituted heteroalkyloxy, heteroaryloxy and substituted
heteroaryloxy.
[0153] Grafting from the surface of the nanoparticle as depicted
above allows formation of a "brush" configuration of polymers. With
reference to FIG. 2, polymers attached to a gadolinium surface can
be spaced differently on a surface. Without wishing to be held to a
specific theory or mechanism of action, the accessibility of the
therapeutic agents and targeting agents to the surrounding
environment can be at least partially controlled by how closely
together the polymers are spaced on the surface of the
nanoparticle. When the distance between the polymers is greater
than the length of the polymer, the polymers adopt a "mushroom"
configuration in which the entirety of the polymer can be
accessible to surrounding environment, including the binding site
of a targeting agent or therapeutic agent attached to the polymer.
Conversely, when the distance between the polymer chains is shorter
than the attached polymer, the polymers have a brush conformation,
in which the terminal portions of the polymer are accessible to the
surrounding environment. If the therapeutic and/or targeting agents
are attached to the terminus of the polymers arranged in a "brush"
conformation, then the therapeutic and/or targeting agents can be
accessible to the surrounding environment.
[0154] Desired polymer configuration on the surface can be achieved
by growing the polymers from the surface of the nanoparticle. In
certain aspects, the polymerization is initiated directly from
substrate via immobilized initiators. The brush polymer
conformation can be achieved by forming the polymer from the
nanoparticle surface, or alternatively by utilizing separately or
combining atom transfer radical polymerization (ATRP) and RAFT
polymerization. Growing the polymers from the surface allows
immobilized polymerization initiators to be tailored for a wide
range of polymerization techniques and substrates.
[0155] In particular, synthesizing polymer brushes requires control
of the polymer molecular weight (i.e. brush thickness), narrow
polydispersities and control of the composition. In the two
examples of generalized RAFT polymerization described above in
Schemes 5 and 6, polymerization occurs prior to grafting to the
gadolinium nanoparticle surfaces (i.e. "grafting to" the
nanoparticle surface).
Functional Groups
[0156] Functional groups are groups that can be covalently linked
to the polymer and/or covalently linked to the therapeutic or
targeting agents, and/or bonded to the nanoparticles. The
functional groups include any group that can be reacted with
another compound to form a covalent linkage between the compound
and the polymer extending from the nanoparticle. Exemplary
functional groups can include carboxylic acids and carboxylic acid
salt derivatives, acid halides, sulfonic acids and sulfonic acid
salts, anhydride derivatives, hydroxyl derivatives, amine and amide
derivatives, silane derivations, phosphate derivatives, nitro
derivatives, succinimide and sulfo-containing succinimide
derivatives, halide derivatives, alkene derivatives, morpholine
derivatives, cyano derivatives, epoxide derivatives, ester
derivatives, carbazole derivatives, azide derivatives, alkyne
derivatives, acid containing sugar derivatives, glycerol analogue
derivatives, maleimide derivatives, protected acids and alcohols,
and acid halide derivatives. The functional groups can be
substituted or unsubstituted, as described herein.
[0157] Functional groups can be attached to the polymer during
polymerization as depicted herein.
[0158] Alternatively, functional groups can be attached to the
polymer backbone via a linker. The term "linker" as used herein
refers to any chemical structure that can be placed between the
polymer and functional group. For example, linkers include a group
including alkyl, substituted alkyl, alkoxy, substituted alkoxy,
acyl, substituted acyl, acylamino, substituted acylamino,
alkylamino, substituted alkylamino, alkylsulfinyl, substituted
alkylsulfinyl, alkylsulfonyl, substituted alkylsulfonyl, alkylthio,
substituted alkylthio, alkoxycarbonyl, substituted alkoxycarbonyl,
aryl, substituted aryl, arylalkyl, substituted arylalkyl, aryloxy,
substituted aryloxy, carbamoyl, substituted carbamoyl, cycloalkyl,
substituted cycloalkyl, cycloheteroalkyl, substituted
cycloheteroalkyl, dialkylamino, substituted dialkylamino, halo,
heteroalkyl, substituted heteroalkyl, heteroaryl, substituted
heteroaryl, heteroarylalkyl, substituted heteroarylalkyl,
heteroalkyloxy, substituted heteroalkyloxy, heteroaryloxy and
substituted heteroaryloxyalkyl groups. In various non-limited
exemplary embodiments, the groups can be from C.sub.1 to C.sub.10,
C.sub.20, or C.sub.30.
[0159] In various embodiments, the linker can include a conjugated
bond, preferably selected from acetylene (--C.dbd.C--, also called
alkyne or ethyne), alkene (--CH.dbd.CH--, also called ethylene),
substituted alkene (--CR.dbd.CR--, --CH.dbd.CR-- and
--CR.dbd.CH--), amide (--NH--CO-- and --NR--CO-- or --CO--NH-- and
--CO--NR--), azo (--N.dbd.N--), esters and thioesters (--CO--O--,
--O--CO--, --CS--O-- and --O--CS--) and other conjugated bonds such
as (--CH.dbd.N--, --CR.dbd.N--, --N.dbd.CH-- and --N.dbd.CR--),
(--SiH.dbd.SiH--, --SiR.dbd.SiH--, --SiR.dbd.SiH--, and
--SiR.dbd.SiR--), (--SiH.dbd.CH--, --SiR.dbd.CH--, --SiH.dbd.CR--,
--SiR.dbd.CR--, --CH.dbd.SiH--, --CR.dbd.SiH--, --CH.dbd.SiR--, and
--CR.dbd.SiR--). Particularly certain bonds are acetylene, alkene,
amide, and substituted derivatives of these three, and azo. The
linker could also be carbonyl, or a heteroatom moiety, wherein the
heteroatom is selected from oxygen, sulfur, nitrogen, silicon or
phosphorus. Thus, suitable heteroatom moieties include, but are not
limited to, --NH and --NR, wherein R is as defined herein;
substituted sulfur; sulfonyl (--SO.sub.2--) sulfoxide (--SO--);
phosphine oxide (--PO-- and --RPO--); and thiophosphine (--PS-- and
--RPS--). The linker could also be a peptidyl spacer such as
Gly-Phe-Leu-Gly.
Therapeutic Agents and Targeting Agents
[0160] Targeting agents and therapeutic agents can be covalently
attached to the polymer. FIG. 3 shows an example of targeting
molecules (folic acid or an RGD sequence) and an example
therapeutic agents (the cancer therapeutics paclitaxel or
methotrexate) binding to a functionalized polymer grafted to a
nanoparticle. The functional groups attach to the polymer backbone
by reaction with the succinimide functional group.
[0161] In various embodiments, the succinimide group of PNAOS
provides an attachment point for a variety of targeting and
therapeutic agents, such as, but not limited to, folic acid, GRGD
sequences, Paclitaxel, and Methotrexate, through pre- and
post-polymerization modification. Unreacted succinimide groups can
further be converted to non-bioactive groups to reduce in vivo side
reactions. Conjugation of therapeutic, targeting, and imaging
agents to the copolymer provides a multifaceted system, which has
potential in decreasing toxicity while increasing efficacy of the
drug due to directed treatment through directed targeting with the
ability to image through optical, magnetic resonance, or computer
tomography.
[0162] It will be understood by those of skill in the art that
various targeting agents or therapeutic agents can be selected for
attachment to functional groups. Further, it will be understood
that a linker can be placed between the functional groups and the
targeting agents and therapeutic agents. The linker can be
cleavable or non-cleavable. For example, in certain instances
therapeutic agents can be cleavable. In certain instances,
diagnostic agents can be non-cleavable.
[0163] Gold nanoparticles themselves can be therapeutic agents.
Alteration of the shape and size of gold nanoparticles has proven a
useful tool to kill cancer cells through near-infrared lasers and
modification with poly(ethylene glycol) polymers has increased
their biocompatibility. T. Niidome, et al., J. Controlled Release,
2006, 114, 343-347.
[0164] Targeting agents are compounds with a specific affinity for
a target compound, such as a cell surface epitope associated with a
specific disease state. Targeting agents may be attached to a
nanoparticle surface to allow targeting of the nanoparticle to a
specific target. Non-limiting examples of targeting agents include
an amino acid sequence including the RGD peptide, an NGR peptide,
folate, Transferrin, GM-CSF, Galactosamine, peptide linkers
including growth factor receptors (e.g. IGF-1R, MET, EGFR),
antibodies and antibody fragments including anti-VEGFR, Anti-ERBB2,
Anti-tenascin, Anti-CEA, Anti-MUC1, Anti-TAG72, mutagenic bacterial
strains, and fatty acids.
[0165] In various embodiments, targeting agents can be chosen for
the different ways in which they interact with tumors. For example,
when the targeting agent folic acid is taken into the cells by the
folate receptors, RGD receptors are expressed on the surface of the
cells, resulting in the nanostructures localizing to the cell
surface. The folate receptor is known to be over expressed in
cancer cells in the case of epithelial malignancies, such as
ovarian, colorectal, and breast cancer, whereas in most normal
tissue it is expressed in very low levels.
[0166] Targeting agents can include any number of compounds known
in the art. In certain situations, the targeting agent specifically
binds to a particular biological target. Nonlimiting examples of
biological targets include tumor cells, bacteria, viruses, cell
surface proteins, cell surface receptors, cell surface
polysaccharides, extracellular matrix proteins, intracellular
proteins and intracellular nucleic acids.
[0167] The nanoparticles and methods described herein are not
limited to any particular targeting agent, and a variety of
targeting agents can be used. The targeting agents can be, for
example, various specific ligands, such as antibodies, monoclonal
antibodies and their fragments, folate, mannose, galactose and
other mono-, di-, and oligosaccharides, and RGD peptide. Examples
of such targeting agents include, but are not limited to, nucleic
acids (e.g., RNA and DNA), polypeptides (e.g., receptor ligands,
signal peptides, avidin, Protein A, and antigen binding proteins),
polysaccharides, biotin, hydrophobic groups, hydrophilic groups,
drugs, and any organic molecules that bind to receptors. In some
instances, a nanoparticle described herein can be conjugated to
one, two, or more of a variety of targeting agents. For example,
when two or more targeting agents are used, the targeting agents
can be similar or dissimilar. Utilization of more than one
targeting agent in a particular nanoparticle can allow the
targeting of multiple biological targets or can increase the
affinity for a particular target.
[0168] In some instances, the targeting agents are antigen binding
proteins or antibodies or binding portions thereof. Antibodies can
be generated to allow for the specific targeting of antigens or
immunogens (e.g., tumor, tissue, or pathogen specific antigens) on
various biological targets (e.g., pathogens, tumor cells, normal
tissue). Such antibodies include, but are not limited to,
polyclonal antibodies; monoclonal antibodies or antigen binding
fragments thereof; modified antibodies such as chimeric antibodies,
reshaped antibodies, humanized antibodies, or fragments thereof
(e.g., Fv, Fab', Fab, F(ab')2); or biosynthetic antibodies, e.g.,
single chain antibodies, single domain antibodies (DAB), Fvs, or
single chain Fvs (scFv).
[0169] Methods of making and using polyclonal and monoclonal
antibodies are well known in the art, e.g., in Harlow et ah, Using
Antibodies: A Laboratory Manual: Portable Protocol I. Cold Spring
Harbor Laboratory (Dec. 1, 1998). Methods for making modified
antibodies and antibody fragments (e.g., chimeric antibodies,
reshaped antibodies, humanized antibodies, or fragments thereof,
e.g., Fab', Fab, F(ab')2 fragments); or biosynthetic antibodies
(e.g., single chain antibodies, single domain antibodies (DABs),
Fv, single chain Fv (scFv), and the like), are known in the art and
can be found, e.g., in Zola, Monoclonal Antibodies: Preparation and
Use of Monoclonal Antibodies and Engineered Antibody Derivatives,
Springer Verlag (Dec. 15, 2000; 1st edition). In some instances,
the antibodies recognize tumor specific epitopes (e.g., TAG-72
(Kjeldsen et al, Cancer Res., 48:2214-2220 (1988); U.S. Pat. Nos.
5,892,020; 5,892,019; and 5,512,443); human carcinoma antigen (U.S.
Pat. Nos. 5,693,763; 5,545,530; and 5,808,005); TP1 and TP3
antigens from osteocarcinoma cells (U.S. Pat. No. 5,855,866);
Thomsen-Friedenreich (TF) antigen from adenocarcinoma cells (U.S.
Pat. No. 5,110,911); "KC-4 antigen" from human prostrate
adenocarcinoma (U.S. Pat. Nos. 4,708,930 and 4,743,543); a human
colorectal cancer antigen (U.S. Pat. No. 4,921,789); CA125 antigen
from cystadenocarcinoma (U.S. Pat. No. 4,921,790); DF3 antigen from
human breast carcinoma (U.S. Pat. Nos. 4,963,484 and 5,053,489); a
human breast tumor antigen (U.S. Pat. No. 4,939,240); p97 antigen
of human melanoma (U.S. Pat. No. 4,918,164); carcinoma or
orosomucoid-related antigen (CORA) (U.S. Pat. No. 4,914,021); a
human pulmonary carcinoma antigen that reacts with human squamous
cell lung carcinoma but not with human small cell lung carcinoma
(U.S. Pat. No. 4,892,935); T and Tn haptens in glycoproteins of
human breast carcinoma (Springer et ah, Carbohydr. Res.,
178:271-292 (1988)), MSA breast carcinoma glycoprotein (Tjandra et
al, Br. J. Surg., 75:811-817 (1988)); MFGM breast carcinoma antigen
(Ishida et al, Tumor Biol, 10: 12-22 (1989)); DU-PAN-2 pancreatic
carcinoma antigen (Lan et al, Cancer Res., 45:305-310 (1985));
CA125 ovarian carcinoma antigen (Hanisch et ah, Carbohydr. Res.,
178:29-47 (1988)); and YH206 lung carcinoma antigen (Hinoda et al,
Cancer J., 42:653-658 (1988)). For example, to target breast cancer
cells, the nanoparticles can be modified with folic acid, EGF, FGF,
and antibodies (or antibody fragments) to the tumor-associated
antigens MUC 1, cMet receptor and CD56 (NCAM).
[0170] Other antibodies that can be used recognize specific
pathogens (e.g., Legionella peomophilia, Mycobacterium
tuberculosis, Clostridium tetani, Hemophilus influenzae, Neisseria
gonorrhoeae, Treponema pallidum, Bacillus anthracis, Vibrio
cholerae, Borrelia burgdorferi, Cornebacterium diphtheria,
Staphylococcus aureus, human papilloma virus, human
immunodeficiency virus, rubella virus, and polio virus).
[0171] In some instances, the targeting agents include a signal
peptide. These peptides can be chemically synthesized or cloned,
expressed and purified using known techniques. Signal peptides can
be used to target the nanoparticles described herein to a discreet
region within a cell. In some situations, specific amino acid
sequences are responsible for targeting the nanoparticles into
cellular organelles and compartments. For example, the signal
peptides can direct a nanoparticle described herein into
mitochondria. In other examples, a nuclear localization signal is
used.
[0172] In other instances, the targeting agent is a nucleic acid
(e.g., RNA or DNA). In some examples, the nucleic acid targeting
agents are designed to hybridize by base pairing to a particular
nucleic acid (e.g., chromosomal DNA, mRNA, or ribosomal RNA). In
other situations, the nucleic acids bind a ligand or biological
target. For example, the nucleic acid can bind reverse
transcriptase, Rev or Tat proteins of HIV (Tuerk et al, Gene,
137(I):33-9 (1993)); human nerve growth factor (Binkley et al, Nuc.
Acids Res., 23(16):3198-205 (1995)); or vascular endothelial growth
factor (Jellinek et al, Biochem., 83(34): 10450-6 (1994)). Nucleic
acids that bind ligands can be identified by known methods, such as
the SELEX procedure (see, e.g., U.S. Pat. Nos. 5,475,096;
5,270,163; and 5,475,096; and WO 97/38134; WO 98/33941; and WO
99/07724). The targeting agents can also be aptamers that bind to
particular sequences.
[0173] The targeting agents can recognize a variety of epitopes on
biological targets (e.g., pathogens, tumor cells, or normal cells).
For example, in some instances, the targeting agent can be sialic
acid to target HIV (Wies et al, Nature, 333:426 (1988)), influenza
(White et al, Cell, 56:725 (1989)), Chlamydia (Infect. Immunol,
57:2378 (1989)), Neisseria meningitidis, Streptococcus suis,
Salmonella, mumps, newcastle, reovirus, Sendai virus, and
myxovirus; and 9-OAC sialic acid to target coronavirus,
encephalomyelitis virus, and rotavirus; non-sialic acid
glycoproteins to target cytomegalovirus (Virology, 176:337 (1990))
and measles virus (Virology, 172:386 (1989)); CD4 (Khatzman et al,
Nature, 312:763 (1985)), vasoactive intestinal peptide (Sacerdote
et al, J. of Neuroscience Research, 18: 102 (1987)), and peptide T
(Ruff et al, FEBS Letters, 211: 17 (1987)) to target HIV; epidermal
growth factor to target vaccinia (Epstein et al, Nature, 318: 663
(1985)); acetylcholine receptor to target rabies (Lentz et al,
Science 215: 182 (1982)); Cd3 complement receptor to target
Epstein-Barr virus (Carel et al, J. Biol. Chem., 265: 12293
(1990)); .beta.-adrenergic receptor to target reovirus (Co et al,
Proc. Natl. Acad. ScL USA, 82: 1494 (1985)); ICAM-I (Marlin et al,
Nature, 344:70 (1990)), N-CAM, and myelin-associated glycoprotein
MAb (Shephey et al, Proc. Natl. Acad. ScL USA, 85:7743 (1988)) to
target rhinovirus; polio virus receptor to target polio virus
(Mendelsohn et al, Cell, 56:855 (1989)); fibroblast growth factor
receptor to target herpes virus (Kaner et al, Science, 248: 1410
(1990)); oligomannose to target Escherichia coli; and ganglioside
GMI to target Neisseria meningitides.
[0174] In other instances, the targeting agent targets
nanoparticles according to the disclosure to factors expressed by
oncogenes. These can include, but are not limited to, tyrosine
kinases (membrane-associated and cytoplasmic forms), such as
members of the Src family; serine/threonine kinases, such as Mos;
growth factor and receptors, such as platelet derived growth factor
(PDDG), SMALL GTPases (G proteins), including the ras family,
cyclin-dependent protein kinases (cdk), members of the myc family
members, including c-myc, N-myc, and L-myc, and bcl-2 family
members.
[0175] In addition, vitamins (both fat soluble and non-fat soluble
vitamins) can be used as targeting agents to target biological
targets (e.g., cells) that have receptors for, or otherwise take
up, vitamins. For example, fat soluble vitamins (such as vitamin D
and its analogs, vitamin E, Vitamin A), and water soluble vitamins
(such as Vitamin C) can be used as targeting agents.
[0176] In some embodiments, antibodies or ligands may be used to
aid in site-specific targeting (T. M. Allen, Nat. Rev. Cancer 2,
750 (October, 2002), Y. S. Park, Biosci. Rep. 22, 267 (April,
2002)). Antibodies and antibody fragments are as described
herein.
[0177] Therapeutic agents include any therapeutic compounds that
are capable of preventing or treating a disease in a patient.
Numerous therapeutic agents are known in the art. Non-limiting
examples of therapeutic agents include doxorubicin, paclitaxel,
methotrexate, cisplatin, camptothecin, vinblastine, aspartic acid
analogues, and short interfering ribonucleic acid (siRNA)
molecules.
[0178] In other embodiments, therapeutic agents can be, but are not
limited to, steroids, analgesics, local anesthetics, antibiotic
agents, chemotherapeutic agents, immunosuppressive agents,
anti-inflammatory agents, antiproliferative agents, antimitotic
agents, angiogenic agents, antipsychotic agents, central nervous
system (CNS) agents; anticoagulants, fibrinolytic agents, growth
factors, antibodies, ocular drugs, and metabolites, analogs,
derivatives, fragments, and purified, isolated, recombinant and
chemically synthesized versions of these species, and combinations
thereof.
[0179] Representative useful therapeutic agents include, but are
not limited to, tamoxifen, paclitaxel, anticancer drugs,
camptothecin and its derivatives, e.g., topotecan and irinotecan,
KRN 5500 (KRN), meso-tetraphenylporphine, dexamethasone,
benzodiazepines, allopurinol, acetohexamide, benzthiazide,
chlorpromazine, chlordiazepoxide, haloperidol, indomethacine,
lorazepam, methoxsalen, methylprednisone, nifedipine, oxazepam,
oxyphenbutazone, prednisone, prednisolone, pyrimethamine,
phenindione, sulfisoxazole, sulfadiazine, temazepam, sulfamerazine,
ellipticin, porphine derivatives for photo-dynamic therapy, and/or
trioxsalen, as well as all mainstream antibiotics, including the
penicillin group, fluoroquinolones, and first, second, third, and
fourth generation cephalosporins. These agents are commercially
available from, e.g., Merck & Co., Barr Laboratories, Avalon
Pharma, and Sun Pharma, among others.
[0180] Additional classes of therapeutic agents include, but are
not limited to, compounds for use in the following therapeutic
areas: antihypertensives, antianxiety agents, antiarrythmia agents,
anticlotting agents, anticonvulsants, blood glucose-lowering
agents, decongestants, antihistamines, antitussives,
antineoplastics, beta blockers, anti-inflammatories, antipsychotic
agents, cognitive enhancers, anti-atherosclerotic agents,
cholesterol-reducing agents, triglyceride-reducing agents,
antiobesity agents, autoimmune disorder agents, anti-impotence
agents, antibacterial and antifungal agents, hypnotic agents,
anti-Parkinsonism agents, anti-Alzheimer's disease agents,
antibiotics, anti-angiogenesis agents, anti-glaucoma agents,
anti-depressants, and antiviral agents.
[0181] Each named therapeutic agent should be understood to include
the nonionized form of the therapeutic agent or pharmaceutically
acceptable forms of the therapeutic agent. By "pharmaceutically
acceptable forms" is meant any pharmaceutically acceptable
derivative or variation, including stereoisomers, stereoisomer
mixtures, enantiomers, solvates, hydrates, isomorphs, polymorphs,
pseudomorphs, neutral forms, salt forms and prodrug agents.
[0182] Additional exemplary therapeutic agents suitable for use in
the nanoparticles include, but are not limited to,
phosphodiesterase inhibitors, such as sildenafil and sildenafil
citrate; HMG-CoA reductase inhibitors, such as atorvastatin,
lovastatin, simvastatin, pravastatin, fluvastatin, rosuvastatin,
itavastatin, nisvastatin, visastatin, atavastatin, bervastatin,
compactin, dihydrocompactin, dalvastatin, fluindostatin,
pitivastatin, and velostatin (also referred to as synvinolin);
vasodilator agents, such amiodarone; antipsychotics, such as
ziprasidone; calcium channel blockers, such as nifedipine,
nicardipine, verapamil, and amlodipine; cholesteryl ester transfer
protein (CETP) inhibitors; cyclooxygenase-2 inhibitors; microsomal
triglyceride transfer protein (MTP) inhibitors; vascular
endothelial growth factor (VEGF) receptor inhibitors; carbonic
anhydrase inhibitors; and glycogen phosphorylase inhibitors. Other
low-solubility therapeutic agents suitable for use in the
nanoparticles are disclosed in US Published patent application
2005/0031692, herein incorporated by reference.
[0183] Therapeutic compounds may also be used to achieve a desired
prophylactic result, i.e. therapeutic compounds may be used
prophylactively. Typically, prophylaxis is achieved prior to or at
an earlier stage of disease than that treated by a therapeutic
compound. Diagnostic compounds aid in determining whether a disease
state exists in a patient. Alternatively, diagnostic compounds may
aid in imaging, or measuring metabolic function.
[0184] In some embodiments, the compounds may be hydrophobic or
partially hydrophobic (J. Lu, et al, Small 3, 1341 (August, 2007)).
Hydrophobic compounds possess non-polar characteristics and thus
not readily soluble in polar environments.
[0185] In other embodiments, the compounds may be or contain
proteins or peptides (Slowing, II, et al, J. Am. Chem. Soc. 129,
8845 (Jul. 18, 2007)). In further embodiments, the compounds may be
DNA, RNA, or other nucleic acids (S. M. Solberg, C. C. Landry, J.
Phys. Chem. B 110, 15261 (Aug. 10, 2006)). Compounds may also
include biologics such as, without wishing to be limited by
example, vaccines, blood products, and peptides. In some
embodiments, more than one type of compound may be included in the
porous framework core.
[0186] The nanoparticles described herein can be used to treat
diseased cells and tissues. In this regard, various diseases are
amenable to treatment using the nanoparticles and methods described
herein. An exemplary, nonlimiting list of diseases that can be
treated with the subject nanoparticles includes breast cancer;
prostate cancer; lung cancer; lymphomas; skin cancer; pancreatic
cancer; colon cancer; melanoma; ovarian cancer; brain cancer; head
and neck cancer; liver cancer; bladder cancer; non-small lung
cancer; cervical carcinoma; leukemia; non-Hodgkins lymphoma,
multiple sclerosis, neuroblastoma and glioblastoma; T and B cell
mediated autoimmune diseases; inflammatory diseases; infections;
hyperproliferative diseases; AIDS; degenerative conditions,
cardiovascular diseases, transplant rejection, and the like. In
some cases, the treated cancer cells are metastatic.
[0187] The route and/or mode of administration of a nanoparticle
described herein can vary depending upon the desired results.
Dosage regimens can be adjusted to provide the desired response,
e.g., a therapeutic response.
[0188] Methods of administration include, but are not limited to,
intradermal, intramuscular, intraperitoneal, intravenous,
subcutaneous, intranasal, epidural, oral, sublingual,
intracerebral, intravaginal, transdermal, rectal, by inhalation, or
topical, particularly to the ears, nose, eyes, or skin. The mode of
administration is left to the discretion of the practitioner.
[0189] In some instances, a nanoparticle described herein is
administered locally. This is achieved, for example, by local
infusion during surgery, topical application (e.g., in a cream or
lotion), by injection, by means of a catheter, by means of a
suppository or enema, or by means of an implant, said implant being
of a porous, non-porous, or gelatinous material, including
membranes, such as sialastic membranes, or fibers. In some
situations, a nanoparticle described herein is introduced into the
central nervous system, circulatory system or gastrointestinal
tract by any suitable route, including intraventricular,
intrathecal injection, paraspinal injection, epidural injection,
enema, and by injection adjacent to the peripheral nerve.
Intraventricular injection can be facilitated by an
intraventricular catheter, for example, attached to a reservoir,
such as an Ommaya reservoir.
[0190] Pulmonary administration can also be employed, e.g., by use
of an inhaler or nebulizer, and formulation with an aerosolizing
agent, or via perfusion in a fluorocarbon or synthetic pulmonary
surfactant.
[0191] A nanoparticle described herein is formulated as a
pharmaceutical composition that includes a suitable amount of a
physiologically acceptable excipient (see, e.g., Remington's
Pharmaceutical Sciences pp. 1447-1676 (Alfonso R. Gennaro, ed.,
19th ed. 1995)). Such physiologically acceptable excipients can be,
e.g., liquids, such as water and oils, including those of
petroleum, animal, vegetable, or synthetic origin, such as peanut
oil, soybean oil, mineral oil, sesame oil and the like. The
physiologically acceptable excipients can be saline, gum acacia,
gelatin, starch paste, talc, keratin, colloidal silica, urea and
the like. In addition, auxiliary, stabilizing, thickening,
lubricating, and coloring agents can be used. In one situation, the
physiologically acceptable excipients are sterile when administered
to an animal. The physiologically acceptable excipient should be
stable under the conditions of manufacture and storage and should
be preserved against the contaminating action of microorganisms.
Water is a particularly useful excipient when a nanoparticle
described herein is administered intravenously. Saline solutions
and aqueous dextrose and glycerol solutions can also be employed as
liquid excipients, particularly for injectable solutions. Suitable
physiologically acceptable excipients also include starch, glucose,
lactose, sucrose, gelatin, malt, rice, flour, chalk, silica gel,
sodium stearate, glycerol monostearate, talc, sodium chloride,
dried skim milk, glycerol, propylene, glycol, water, ethanol and
the like. Other examples of suitable physiologically acceptable
excipients are described in Remington's Pharmaceutical Sciences pp.
1447-1676 (Alfonso R. Gennaro, ed., 19th ed. 1995). The
pharmaceutical compositions, if desired, can also contain minor
amounts of wetting or emulsifying agents, or pH buffering
agents.
[0192] Liquid carriers can be used in preparing solutions,
suspensions, emulsions, syrups, and elixirs. A nanoparticle
described herein can be suspended in a pharmaceutically acceptable
liquid carrier such as water, an organic solvent, a mixture of
both, or pharmaceutically acceptable oils or fat. The liquid
carrier can contain other suitable pharmaceutical additives
including solubilizers, emulsifiers, buffers, preservatives,
sweeteners, flavoring agents, suspending agents, thickening agents,
colors, viscosity regulators, stabilizers, or osmo-regulators.
Suitable examples of liquid carriers for oral and parenteral
administration include water (particular containing additives
described herein, e.g., cellulose derivatives, including sodium
carboxymethyl cellulose solution), alcohols (including monohydric
alcohols and polyhydric alcohols, e.g., glycols) and their
derivatives, and oils (e.g., fractionated coconut oil and arachis
oil). For parenteral administration the carrier can also be an oily
ester such as ethyl oleate and isopropyl myristate. The liquid
carriers can be in sterile liquid form for administration. The
liquid carrier for pressurized compositions can be halogenated
hydrocarbon or other pharmaceutically acceptable propellant.
[0193] In other instances, a nanoparticle described herein is
formulated for intravenous administration. Compositions for
intravenous administration can comprise a sterile isotonic aqueous
buffer. The compositions can also include a solubilizing agent.
Compositions for intravenous administration can optionally include
a local anesthetic such as lignocaine to lessen pain at the site of
the injection. The ingredients can be supplied either separately or
mixed together in unit dosage form, for example, as a dry
lyophilized powder or water-free concentrate in a hermetically
sealed container such as an ampule or sachette indicating the
quantity of active agent. Where a nanoparticle described herein is
administered by infusion, it can be dispensed, for example, with an
infusion bottle containing sterile pharmaceutical grade water or
saline. Where a nanoparticle described herein is administered by
injection, an ampule of sterile water for injection or saline can
be provided so that the ingredients can be mixed prior to
administration.
[0194] In other circumstances, a nanoparticle described herein can
be administered across the surface of the body and the inner
linings of the bodily passages, including epithelial and mucosal
tissues. Such administrations can be carried out using a
nanoparticle described herein in lotions, creams, foams, patches,
suspensions, solutions, and suppositories (e.g., rectal or
vaginal). In some instances, a transdermal patch can be used that
contains a nanoparticle described herein and a carrier that is
inert to the nanoparticle described herein, is non-toxic to the
skin, and that allows delivery of the agent for systemic absorption
into the blood stream via the skin. The carrier can take any number
of forms such as creams or ointments, pastes, gels, or occlusive
devices. The creams or ointments can be viscous liquid or semisolid
emulsions of either the oil-in-water or water-in-oil type. Pastes
of absorptive powders dispersed in petroleum or hydrophilic
petroleum containing a nanoparticle described herein can also be
used. A variety of occlusive devices can be used to release a
nanoparticle described herein into the blood stream, such as a
semi-permeable membrane covering a reservoir containing the
nanoparticle described herein with or without a carrier, or a
matrix containing the nanoparticle described herein.
[0195] Therapeutic agents and targeting agents can be covalently
attached to the polymer by RAFT synthesis. The therapeutic agent or
targeting agent is configured to be added to the RAFT polymer
during polymerization. As such the therapeutic agent and targeting
agent can be linked directly to the RAFT polymer. Those of skill in
the art will recognize that a linker can be added between the
therapeutic agent or targeting agent and the polymer.
[0196] Alternatively, therapeutic agents and targeting agents are
linked to the polymer via a functional group as described above.
Those of skill in the art will recognize that a linker can be added
between the therapeutic agent or targeting agent and the
polymer.
[0197] Multifunctional synthesis of compounds can be accomplished
by RAFT polymerization as depicted in the example of Scheme 7.
##STR00015##
[0198] In this embodiment, a succinimide group can be used to
attach a functional group to the nanoparticle. An example of
biocompatible copolymers containing functional
N-acryloyloxysuccinimide (NAOS) monomer units can also be
synthesized via RAFT polymerization. A range of copolymer backbones
can be used, including, but not limited to, N-isopropylacrylamide
(NIPAM), N,N-dimethylaminoethyl acrylate (DMAEA), and poly(ethylene
glycol) methyl ether acrylate (PEGMEA). The addition of NAOS into
the copolymer backbones has been achieved at a range of weight
percents as a means of attachment. The copolymers were synthesized
utilizing the well-known trithiocarbonate DATC in dioxane at 60 or
70 degrees, with a fluorescein monomer incorporated near the end of
the polymerization. The polymers were characterized via both proton
NMR and GPC.
[0199] In various embodiments, unreacted succinimide groups can
further be converted to non-bioactive groups to reduce in vivo side
reactions.
[0200] In Scheme 8, a folic acid targeting agent is attached to the
succinimide functional group.
##STR00016##
[0201] FIG. 4a depicts a .sup.1H NMR spectrum of
PNIPAM-co-PNAOS-co-PFMA copolymer. FIG. 4b depicts a .sup.1H NMR
spectra of folic acid. FIG. 4c depicts a .sup.1H NMR spectrum of
PNIPAM copolymer reacted with folic acid.
Imaging Agents
[0202] A particularly interesting aspect of nanomedicines is
multimodal imaging agents. Biomedical imaging and diagnostic
techniques such as computed X-ray tomography (CT), magnetic
resonance imaging (MRI), optical imaging (OI) and positron emission
tomography (PET) are useful in modern clinical settings for the
diagnosis of various diseases. While these imaging techniques have
been responsible for tremendous advances in clinical diagnosis,
each has its own advantages and drawbacks, and no single technique
includes all the required capabilities for comprehensive biomedical
imaging.
[0203] Imaging agents can be covalently attached to the polymer.
The imaging agents may be attached to a functionalized group on the
polymer backbone grafted to a nanoparticle. The functional groups
attach to the polymer backbone by reaction with the succinimide
functional group. Those of skill in the art will recognize that
many different imaging agents that can be attached to the polymer
backbone. Without being limited to specific embodiments, imaging
agents can be chosen from the group comprising fluorescence agents,
radiological agents, and positron emission agents.
[0204] Current magnetic resonance imaging (MRI) techniques employ
gadolinium as a contrast agent. In certain embodiments, gadolinium
metal is highly toxic to cells. For MRI application, this toxicity
has been overcome by utilizing chelates to increase stability and
compatibility of the metal ion. However, concerns have arisen with
current in vivo use of gadolinium chelates due to non-specific
cellular uptake and accumulation within healthy cells. W. A. High,
J. Am. Acad. Dermatol. 2006, 56, 21-26. Several groups have
attempted to overcome these issues by using cascade polymers and
dendrimers, however size distribution and spatial loading is poor.
Id. Gadolinium oxide nanoparticles have proven to be interesting
because of their effectiveness as MRI contrast agents. J. L.
Bridot, J. Am. Chem. Soc. 2007. H. Hifumi, J. Am. Chem. Soc. 2006,
128, 15090-15091, W. J. Rieter, J. Am. Chem. Soc. 2006, 128,
9024-9025. M. O. Oyewumi, Journal of Controlled Release 2004, 95,
613-626. Modification of these particles with polymers shows
promise as a means to compatiblize the surface of gadolinium
nanoparticles for in vivo imaging and to affix moieties that will
potentially allow for targeting and treatment of cancer cells
through control of nanoparticle-cellular surface interactions.
Though recent advances have been made in the synthesis and
modification of metal nanoparticles, such as gold nanorods, the
modification and characterization of metal oxide frameworks, such
as gadolinium oxide nanoparticles, is still limited.
[0205] Fluorescence agents can be visualized in the visible or
near-visible spectra. Fluorescence agents [such as PFMA are induced
to emit photons by exciting electrons in the molecules by exposure
to light energy, typically violet or ultraviolet light.].
Radiological agents are molecules possessing radioactive material
that can be detected by detection of the radioactive decay.
Positron emission tomography (PET) agents contain radioactive
materials that can be detected by a gamma or PET scanner.
[0206] It will be understood by those of skill in the art that
various imaging agents can be selected for attachment to functional
groups. Further, it will be understood that a linker can be placed
between the functional groups and the imaging agents. The linker
can be cleavable or non-cleavable. For example, in certain
instances imaging agents can be cleavable. In certain instances,
imaging agents can be non-cleavable.
[0207] Without wishing to be limited by specific embodiments,
Gold/Lanthanide nanoparticles can be modified with a well-defined
RAFT copolymer,
PNIPAM-co-poly(N-acryloxysuccinmide)(PNAOS)-co-poly(fluorescein
O-methacrylate) (PFMA). Incorporation of the PFMA monomer into the
backbone of the copolymer provides a means measuring polymer
incorporation in vitro by fluorescence imaging. In order to confirm
the ability of these copolymer modified hybrid nanoparticles to be
imaged by fluorescence microscopy, a fluorescence scanner was
employed to provide the images of PNIPAM-co-PNAOS-co-PFMA modified
gold/Gd nanoparticles (FIG. 5). Fluorescence of these particles is
readily detectible in copolymer modified gold/lanthanide
nanoparticles.
Multimodal Imaging
[0208] In some aspects different imaging agents may be combined to
produce a multimodal imaging agent. By way of example and not
limition, multimodal imaging agents may combine PET and CT, PET and
MRI, or MRI and OI. (Bakalova et al, Multimodal Silica Shelled
Quantum Dots: Direct Intracellular Delivery, Photosensitization,
Toxic, and Microcirculation Effects. Bioconjugate Chem. 19,
1135-1142 (2008); Frullano, L., Meade, T. J. Multimodal MRI
Contrast Agents. J. Biol. Inorg. Chem. 12, 939-949 (2007)) In some
aspects, these imaging techniques may be complimentary, rather than
competitive, and so may aid in minimizing artifacts and enabling
precise comparative analysis of images obtained by the different
techniques. (Frullano, L., Meade, T. J. Multimodal MRI Contrast
Agents. J. Biol. Inorg. Chem. 12, 939-949 (2007)).
[0209] Gadolinium Based Imaging
[0210] MRI, magnetic resonance imaging, involves measuring the
nuclear magnetic resonance (NMR) of water protons in a specimen.
This may be performed by placing a subject in a magnetic field that
may re-orient protons and measuring the time for the affected
protons to relax. Protons in differing chemical environments will
exhibit different relaxation times. The observed contrast in MRI
essentially depends on factors such as the water proton density,
the longitudinal relaxation time (T1), and the transverse
relaxation time (T2) of these protons. Contrast agents may be used
in MRI to aid in diagnostic imaging.
[0211] Gadolinium may be used to enhance MRI. (Aime et al,
R.sub.2/R.sub.1 Ratiometric Procedure for a
Concentration-Independent, pH-Responsive, Gd(III)-Based MRI Agent.
J. Am. Chem. Soc. 128, 11326-11327 (2006); Bridot et al., Hybrid
Gadolinium Oxide Nanoparticles: Multimodal Contrast Agents for in
Vivo Imaging. J. Am. Chem. Soc. 129, 5076-5084 (2007); Hifumi et
al., Gadolinium-Based Hybrid Nanoparticles as a Positive MR
Contrast Agent. J. Am. Chem. Soc. 128, 15090-15091 (2006)). MRI
agents may work by increasing the contrast (or relaxation rate of
protons) between the particular organ or tissue of interest and the
surrounding tissues in the body. (Caravan, P., Ellison, J. J.,
McMurry, T. J., Lauffer, R. B. Gadolinium(III) Chelates as MRI
Contrast Agents: Structure, Dynamics, and Application. Chem. Rev.
99, 2293-2352 (1999).) These agents may have a local effect on T1
and T2 relaxation times. In one aspect, relaxivity of water protons
may be altered by introducing a high spin paramagnetic metal into
the system. For example, gadolinium (Gd), may be used to alter
proton relaxation times. In some aspects, water molecules bound to
Gd may relax orders of magnitude faster than free water, resulting
in dramatic changes in T1 where Gd is present. Gadolinium(III)
(Gd.sup.3+) complexes may have a high longitudinal relaxivity
(r.sub.1) and thus have an effect mostly on T1-relaxation times of
surrounding water protons (as described in Caravan et al.,
Gadolinium(III) Chelates as MRI Contrast Agents: Structure,
Dynamics, and Application. Chem. Rev. 99, 2293-2352 (1999)). This
enhanced T1-relaxation time may lead to an increase in signal
intensity in T1-weighted images.
[0212] Gold Based Imaging
[0213] Gold (Au), because of its high atomic number and X-ray
absorption coefficient may be used to in various imaging techniques
known in the art. (Kim, D., Park, S., Lee, J. H., Jeong, Y. Y.,
Jon, S. Antibiofouling Polymer-Coated Gold Nanoparticles as a
Contrast Agent for in Vivo X-ray Computed Tomography Imaging. J.
Am. Chem. Soc. 129, 7661-7665 (2007); Su, C.-H., Sheu, H.-S., Lin,
C.-Y., Huang, C.-C., Lo, Y.-W., Pu, Y.-C., Weng, J.-C., Shieh,
D.-B., Chen, J.-H., Yeh, C.-S, Nanoshell Magnetic Resonance Imaging
Contrast Agents. J. Am. Chem. Soc. 129, 2139-2146 (2007); Huang,
X., EI-Sayed, I. H., Qian, W., El-Sayed, M. A. Cancer Cell Imaging
and Photothermal Therapy in the Near-Infrared Region by Using Gold
Nanorods. J. Am. Chem. Soc. 128, 2115-2120 (2006)). By way of
example and not limitation, gold nanoparticles may be used to
enhance images produced by X-ray computed tomography (CT; as
described in Kim et al, Antibiofouling Polymer-Coated Gold
Nanoparticles as a Contrast Agent for in Vivo X-ray Computed
Tomography Imaging. J. Am. Chem. Soc. 129, 7661-7665 (2007)), and
dark field and confocal microscopy (as described in Huang, X.,
EI-Sayed, I. H., Qian, W., EI-Sayed, M. A. Cancer Cell Imaging and
Photothermal Therapy in the Near-Infrared Region by Using Gold
Nanorods. J. Am. Chem. Soc. 128, 2115-2120 (2006)). Dark field and
confocal microscopy are optical imaging techniques that may aid
visualization by increasing contrast. CT is a non-optical imaging
technique that may involve constructing a three dimensional
representation of a specimen from a series of two dimensional X-ray
images.
Other Methods
[0214] Aside from the in vivo diagnosis and treatment of cancer,
with attachment of appropriate therapeutics and/or targeting
moieties and/or imaging agents, the invention may be used for a
wide variety of different drug delivery applications, such as gene
therapy, imaging applications, such as vascular imaging, and even
in external molecular detection devices, such as microarrays and
assays. The primary industry interested in the invention would be
pharmaceutical companies. While these applications have been
mentioned specifically there may be many more applications that the
inventors have not considered or are yet to be thought of for the
invention.
EXAMPLES
[0215] The following examples are intended to be exemplary, and not
limit, the present disclosure.
Example 1
Synthesis of Gold/Gadolinium Nanoparticles
[0216] Gold nanoparticles were synthesized via procedures described
herein. As shown in FIG. 6(a), one embodiment resulted in
synthesized gold nanoparticles having an average length of 250 nm
and width of 30 nm, providing an aspect ratio (length/width) of
about 8 nm. Those of skill in the art will appreciate that the
average dimensions of gold nanoparticles can be easily tuned with
slight changes to the experimental procedures.
[0217] Gold nanoparticles were subsequently coated with a Gd-based
nanoscale metal organic framework (NMOF). Coating of the gold
nanoparticles was accomplished by taking advantage of a reverse
microemulsion system, discussed in the literature and depicted in
FIG. 1. In one embodiment reverse microemulsion provides Gd-based
NMOFs. For Gd-based NMOFs, aqueous solutions of GdCl.sub.3 (0.5M)
and 1,4-benzenedicarboxylic acid (1,4-BDC) (0.075M) were first
prepared separately. Next, the GdCl.sub.3 and 1,4-BDC aqueous
solutions were combined into a
heptane/hexanol/cetyltrimethylammonium bromide (0.05M)
microemulsion. This was followed by addition of the gold
nanoparticles into the microemulsion reaction. The
nanoparticle/gadolinium mixture was then stirred vigorously for 24
hours at room temperature.
[0218] After 24 h, the microemulsion mixture was centrifuged; the
supernatant removed, and the nanoparticles subjected to three cyles
of ethanol-wash/sonication/centrifugation. The supernatant was
collected and discarded. The gold/gadolinium nanoparticles were
then subjected to one last wash in deionized water followed by
centrifugation and then storage in fresh deionized water. The
gold/Gd nanoparticles were characterized by TEM (transmission
electron microscopy), UV-Vis (ultraviolet visual) spectroscopy, and
ATR-FTIR (attenuated total reflection-fourier transform
infrared).
[0219] Transmission Electron Microscopy, TEM, was used to visualize
and measure the Gd-coated gold nanoparticles. TEM identified a
uniform Gd-based coating of the gold nanoparticles with an average
thickness of 4 nm (FIG. 6b).
[0220] Ultraviolet-Violet spectroscopy was also used to analyze the
Gd-coated gold nanoparticles. This technique was first used to
analyze the virgin gold nanoparticles (FIG. 7), which gave a
wavelength maximum for the transverse surface plasmon peak of 532
nm. Coating these particles with Gd-based metal organic framework
resulted in a red shift of the transverse surface plasmon peak
maximum to 535 nm (FIG. 7). This 3 nm red shift correlated well to
the thickness of the surface coating measured by TEM (FIG. 6b).
[0221] Finally, ATR-FTIR was also used to analyze the gadolinium
coated nanoparticles. ATR-FTIR was used to probe the structure of
the gadolinium-coated gold nanoparticles (FIG. 8). The
gadolinium-coated gold nanoparticles produced a spectrum with a
characteristic out-of-plane .dbd.C--H aromatic stretch at 725
cm.sup.-1, symmetric carboxylate stretch at 1450 cm.sup.-1, an
assymetric carboxylate stretch at 1520 cm.sup.-1, along with 2855
cm.sup.-1, 2925 cm.sup.-1, and 3065 cm.sup.-1. These peaks are
attributed to the --C--H stretching vibrations of the 1,4-BDC
bridging ligand ligand. There was also a 3460 cm.sup.-1 peak which
was attributed to the --OH stretch of the water ligand.
[0222] Thus these techniques confirmed the presence of a gadolinium
coating on the gold nanoparticles that was measured to be
approximately 3 to 4 nm thick.
Example 2
Polymer Surface Modification of Au--Gd Hybrid Nanoparticles
[0223] Scheme 1. Au/Gd hybrid nanoparticles were modified with
well-defined homopolymers and copolymers synthesized via reversible
addition-fragmentation chain transfer (RAFT) polymerization.
Without being limited to a specific mechanism or mode of action,
one mechanism of attachment is shown in FIG. 1d. In the mechanism
depicted in FIG. 1d, a thiolate terminated polymer is covalently
attached to the nanoparticle surface through a coordination
reaction between the polymer chain thiolate end-group moiety and
vacant orbitals on the Gd.sup.3+ ions at the surface of the Gd
nanoparticles.
[0224] In one embodiment, DATC was employed as the RAFT agent in
the formation of homopolymers by RAFT polymerization. This
DATC/RAFT reaction yields trithiocarbonate terminated chains. Au/Gd
hybrid nanoparticles were modified with poly(N-isopropylacrylamide)
(PNIPAM) homopolymer in N,N-dimethylformamide with the use of
hexylamine as a reducing agent (Scheme 2). Modification of Au/Gd
nanoparticles was achieved by an initial aminolysis, using
hexylamine, of the trithiocarbonate end group of the RAFT
homopolymer to a thiolate functionality under inert and basic
conditions. Subsequently, the thiolate terminated homopolymer was
covalently attached to the nanoparticle surface through a
coordination reaction between the polymer and Gd3+.
[0225] After polymer deposition and prior to characterization or
use, the nanoparticles were washed several times with a good
solvent in order to remove any free polymer from the system.
[0226] The polymer modification of the Au/Gd nanoparticles with the
PNIPAM homopolymer was analyzed by TEM (FIG. 6), UV-Vis
spectroscopy (FIG. 7), and ATR-FTIR (FIG. 8). All three methods
confirmed the presence of polymer modification on the
nanoparticle.
[0227] TEM was again used to measure the thickness of the
gold/gadolinium/polymer surface. This technique resulted in a
measurement for the thickness of the gadolinium/polymer layer of
approximately 8 nm. Subtracting out the apparent thickness of the
gold/gadolinium layer (4 nm) suggested that the polymer layer was 4
nm thick. These values agreed well with results obtained by surface
plasmon shift/UV-Vis spectroscopy.
[0228] FIG. 7 shows that the maximum surface plasmon peak of the
gold/gadolinium/polymer nanoparticles occurred at 544 nm. Comparing
the UVN is spectra of gold nanoparticles, gold/gadolinium
nanoparticles, and gold/gadolinium/polymer nanoparticles showed a
12 nm shift in surface plasmon peak between the gold nanoparticle
and the gold/gadolinium/polymer nanoparticles. This represents a 9
nm red shift from gold/gadolinium nanoparticle to
gold/gadolinium/polymer nanoparticle.
[0229] Finally, ATR-FTIR analysis identified significant N--H
bonding and other changes in the spectrum of Au/Gd polymer
nanoparticles compared to unmodified Au/Gd nanoparticles or
homopolymer (FIG. 8). Several of the characteristic stretches of
the free PNIPAM homopolymer, including a broad N--H stretch above
3300 cm.sup.-1 and a small N--H bend at 1640 cm.sup.-1 indicating
the presence of the acrylamide functionality; an increase in
intensity of the --CH2 stretching and C--H stretching vibrations
between 2800-3000 cm.sup.-1 due to backbone methylenes; a peak at
1720 cm.sup.-1 assigned to the carbonyl stretch of the amide; and a
stretch at 1380 cm.sup.-1 attributed to the addition of --CH3 and
isopropyl groups, display good transference to the polymer modified
Au/Gd hybrid nanoparticles, when compared to the unmodified Au/Gd
hybrid nanoparticles (FIG. 8).
[0230] Scheme 2. Surface Modification of Au/Gd Hybrid Nanoparticles
by Incorporation of Optical Imaging Agents into Polymer Backbone.
Fluorescence imaging was used to analyze polymer modification of
Au/Gd nanoparticles. Incorporation of a poly(fluorescein
O-methacrylate) monomer into the backbone of the copolymer would
provide a means for measuring polymer incorporation through the use
of in vitro fluorescence imaging. To do this, Au/Gd hybrid
nanoparticles were first modified with a fluorescent RAFT
copolymer,
PNIPAM-co-poly(N-acryloxysuccinmide)(PNAOS)-co-poly(fluorescein
O-methacrylate) (PFMA).
[0231] A fluorescence scanner was used in order to confirm
incorporation and provide images of fluorescent gold/Gd
nanoparticles. FIG. 5 is a flourescence image of gold/gadolinium
nanoparticles coated with a fluorescent copolymer.
Example 3
Biocompatibilty of Gold/Gadolinium Nanoparticles
[0232] The ability of modified and unmodified Au/Gd nanoparticles
to inhibit cell growth was compared in vitro.
[0233] To test the biocompatibility of the unmodified and polymer
modified gold/Gd nanoparticles, growth inhibition studies were
performed using a canine endothelial hemangiosarcoma (FITZ-HSA)
tumor cells. Samples were incubated with FITZ-HSA at 37.degree. C.
in standard culture medium containing 10% PBS for 72 h in a 5% CO2
atmosphere. Each of the components for the nanodevice synthesis,
gold nanoparticles, RAFT copolymer, along with the unmodified and
polymer-modified gold/Gd nanoparticles were tested. As can be seen
in FIG. 9, the unmodified gold nanoparticles resulted in
significant cell growth inhibition at high concentrations. This is
most likely due to residual CTAB absorbed on the surface of the
gold nanoparticles. However, note that modification of the gold
nanoparticles to form the gold/Gd nanoparticles and further
modification of the gold/Gd nanoparticles did not decrease cell
viability. The increased cell viability is attributed to coating of
the gold/Gd nanoparticles with copolymers consisting of the
biocompatible polymer PNIPAM. This infers that the presence of the
RAFT copolymer on the surface of the gold/Gd nanoparticles
increases the biocompatible nature of the nanodevice.
[0234] In vitro MRI of GdNPs and Polymer Modified Gd NPs. In order
to provide information about the clinical imaging viability of the
polymer modified gold/Gd nanoparticles, as a positive contrast
agent, in vitro MRI was employed to determine relaxation properties
of the unmodified and polymer modified gold/Gd nanoparticles. Table
1 compares the MRI longitudinal and transverse relaxivities, r1 and
r2, respectively, of PNIPAM-modified gold/Gd nanoparticles and
gold/Gd unmodified nanoparticles to the clinically employed
contrasts agents, gadopentetate dimeglumine (Magnevist.RTM.) and
gadobenate dimeglumine (Multihance.RTM.). The calculated
relaxivities demonstrate that both the unmodified and polymer
modified Gd NPs result in a large shortening of the T1 relaxation
time and, thus, behave as positive contrast agents. Additionally,
the ratio of the transverse and longitudinal relaxivities of the
unmodified and polymer modified gold/Gd nanoparticles are less than
that of the clinically employed contrast agents, Magnevist.RTM. and
Multihance.RTM., suggesting that unmodified and polymer-modified Gd
NPs should produce potentially feasible clinically useful T1
shortening effects, in comparison to currently employed contrast
agents. By taking advantage of these properties, novel theragnostic
polymer-modified gold/Gd nanoparticles could be produced and
exploited as contrast agents for conventional T1 MR imaging.
TABLE-US-00001 TABLE 1 MRI relaxivity values for clinical MRI
contrast agents, Multihance .RTM. and Magnevist .RTM., along with
the unmodified and polymer modified gold/Gd nanoparticles. Contrast
Agent r.sub.1 (mM/L) r.sub.2 (mM/L) r.sub.2/r.sub.1 Magnevist .RTM.
6.95 17.41 2.51 Multihance .RTM. 17.70 35.57 2.01 Unmodified Au--Gd
Hybrid NPs 6.08 8.22 1.35 PNIPAM Homopolymer Modified 11.28 18.83
1.67 Au--Gd Hybrid NPs PNIPAM Copolymer Modified 13.55 21.85 1.61
Au--Gd Hybrid NPs
[0235] Applicants further note that the compounds and methods
disclosed herein include those compounds cited in U.S. 2007/0123670
to McCormick et al., which is incorporated herein by reference in
its entirety.
[0236] All references cited herein are incorporated herein by
reference in their entirety.
* * * * *
References